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Cryptarithmetic puzzle

Cryptarithmetic, also known as alphametics or cryptarithms, is a type of mathematical puzzle where mathematical operations are represented by letters or symbols. The goal of the puzzle is to find the numerical values that each letter or symbol represents, so that the mathematical equation is true.

In a typical cryptarithmetic puzzle, a set of letters or symbols represent digits in a simple arithmetic equation. For example, the letters A, B, and C might represent the digits 2, 5, and 7 respectively. The puzzle would then be to find the value of the expression "AB + C" which would be equivalent to a known value, say 19.

The challenge in solving a cryptarithmetic puzzle is to find the correct assignment of digits to letters, so that the arithmetic expression is valid. This is usually done through a process of trial and error, by testing different combinations of digits until a solution is found.

Code Solution

/*
    C program for
    Cryptarithmetic puzzle
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// Define node which is contain letter and resultant value
struct Node
{
	char letter;
	int value;
};
// 
int isValid(struct Node *result, int count , const char *s1 , const char *s2 , const char *s3)
{
	int v1 = 0;
	int v2 = 0;
	int v3 = 0;
	// Loop controlling variables
	int i = 0;
	int j = 0;
	int multiplier = 1;
	for (i = strlen(s1) - 1; i >= 0; i--)
	{
		j = 0;
		while (j < count && result[j].letter != s1[i])
		{
			j++;
		}
		v1 = v1 + multiplier *result[j].value;
		multiplier *= 10;
	}
	multiplier = 1;
	for (i = strlen(s2) - 1; i >= 0; i--)
	{
		j = 0;
		while (j < count && result[j].letter != s2[i])
		{
			j++;
		}
		v2 = v2 + multiplier *result[j].value;
		multiplier *= 10;
	}
	multiplier = 1;
	for (i = strlen(s3) - 1; i >= 0; i--)
	{
		j = 0;
		while (j < count && result[j].letter != s3[i])
		{
			j++;
		}
		v3 = v3 + multiplier *result[j].value;
		multiplier *= 10;
	}
	if (v3 == (v1 + v2))
	{
		return 1;
	}
	else
	{
		return 0;
	}
}
// Find solution
int permutation(int count, int use[], struct Node *result, int n , const char *s1 , const char *s2 , const char *s3)
{
	// Loop controlling variables
	int i = 0;
	int j = 0;
	if (n == count - 1)
	{
		for (i = 0; i < 10; i++)
		{
			if (use[i] == 0)
			{
				result[n].value = i;
				if (isValid(result, count, s1, s2, s3) == 1)
				{
					return 1;
				}
			}
		}
		return 0;
	}
	for (i = 0; i < 10; i++)
	{
		if (use[i] == 0)
		{
			result[n].value = i;
			use[i] = 1;
			if (permutation(count, use, result, n + 1, s1, s2, s3) == 1)
			{
				// When get a result 
				return 1;
			}
			use[i] = 0;
		}
	}
	return 0;
}
// Calculate the frequency of character
void frequency(int freq[] , const char *str)
{
	int i = 0;
	int len = strlen(str);
	// Calculate character frequency of givens const char *
	for (i = 0; i < len; i++)
	{
		freq[str[i] - 'A']++;
	}
}
// Cryptarithmetic handles requests to solve puzzles
void cryptarithmeticPuzzle(const char *s1 , const char *s2 , const char *s3)
{
	// Use to count frequency of each character
	int freq[26];
	// Use to count of unique characters
	int count = 0;
	// Loop controlling variables 
	int i = 0;
	int j = 0;
	// Set initial frequency
	for (i = 0; i < 26; i++)
	{
		freq[i] = 0;
	}
	// Count frequency of each character in a given const char *( form of A-Z).
	frequency(freq, s1);
	frequency(freq, s2);
	frequency(freq, s3);
	// Count the number of repeating elements
	for (i = 0; i < 26; i++)
	{
		if (freq[i] > 0)
		{
			// When element occurrences
			count++;
		}
	}
	if (count > 10)
	{
		// When string are not valid
		printf("Invalid string");
	}
	else
	{
		// Use to track numbers
		int use[10];
		struct Node *result = (struct Node *) malloc(sizeof(struct Node) *count);
		for (i = 0, j = 0; i < 26; i++)
		{
			if (freq[i] > 0)
			{
				// Set node value
				result[j].letter = i + 'A';
				result[j].value = 0;
				// visit to next node
				j++;
			}
		}
		// Set initial values
		for (i = 0; i < count; ++i)
		{
			// Here zero indicate empty slot
			use[i] = 0;
		}
		if (permutation(count, use, result, 0, s1, s2, s3) == 1)
		{
          	printf(" Given : %s  %s  %s \n",s1,s2,s3);
          	printf(" Solution  \n");
			// Display solution
			for (j = 0; j < count; j++)
			{
				printf(" %c =  %d ", result[j].letter, result[j].value);
			}
		}
		else
		{
			// When no solution
			printf("No Result");
		}
		free(result);
		result = NULL;
	}
}
int main()
{
	const char *s1 = "SUN";
	const char *s2 = "RUN";
	const char *s3 = "FAST";
	// Test
	cryptarithmeticPuzzle(s1, s2, s3);
}

Output

 Given : SUN  RUN  FAST
 Solution
 A =  0  F =  1  N =  2  R =  3  S =  6  T =  4  U =  8
/*
    Java Program for
    Cryptarithmetic puzzle
*/
// Define node which is contain letter and resultant value
class Node
{
	public char letter;
	public int value;
	public Node()
	{
		this.letter = ' ';
		this.value = 0;
	}
};
// Binary Tree
public class Puzzle
{
	public boolean isValid(Node[] result, int count, String s1, String s2, String s3)
	{
		int v1 = 0;
		int v2 = 0;
		int v3 = 0;
		// Loop controlling variables
		int i = 0;
		int j = 0;
		int multiplier = 1;
		for (i = s1.length() - 1; i >= 0; i--)
		{
			j = 0;
			while (j < count && result[j].letter != s1.charAt(i))
			{
				j++;
			}
			v1 = v1 + multiplier * result[j].value;
			multiplier *= 10;
		}
		multiplier = 1;
		for (i = s2.length() - 1; i >= 0; i--)
		{
			j = 0;
			while (j < count && result[j].letter != s2.charAt(i))
			{
				j++;
			}
			v2 = v2 + multiplier * result[j].value;
			multiplier *= 10;
		}
		multiplier = 1;
		for (i = s3.length() - 1; i >= 0; i--)
		{
			j = 0;
			while (j < count && result[j].letter != s3.charAt(i))
			{
				j++;
			}
			v3 = v3 + multiplier * result[j].value;
			multiplier *= 10;
		}
		if (v3 == (v1 + v2))
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	// Find solution
	public boolean permutation(int count, boolean[] use, Node[] result, int n, String s1, String s2, String s3)
	{
		// Loop controlling variables
		int i = 0;
		int j = 0;
		if (n == count - 1)
		{
			for (i = 0; i < 10; i++)
			{
				if (use[i] == false)
				{
					result[n].value = i;
					if (isValid(result, count, s1, s2, s3) == true)
					{
						return true;
					}
				}
			}
			return false;
		}
		for (i = 0; i < 10; i++)
		{
			if (use[i] == false)
			{
				result[n].value = i;
				use[i] = true;
				if (permutation(count, use, result, n + 1, s1, s2, s3) == true)
				{
					// When get a result 
					return true;
				}
				use[i] = false;
			}
		}
		return false;
	}
	// Calculate the frequency of character
	public void frequency(int[] freq, String str)
	{
		int i = 0;
		int len = str.length();
		// Calculate character frequency of givens String *
		for (i = 0; i < len; i++)
		{
			freq[str.charAt(i) - 'A']++;
		}
	}
	// Cryptarithmetic handles requests to solve puzzles
	public void cryptarithmeticPuzzle(String s1, String s2, String s3)
	{
		// Use to count frequency of each character
		int[] freq = new int[26];
		// Use to count of unique characters
		int count = 0;
		// Loop controlling variables 
		int i = 0;
		int j = 0;
		// Set initial frequency
		for (i = 0; i < 26; i++)
		{
			freq[i] = 0;
		}
		// Count frequency of each character in a given String *( form of A-Z).
		frequency(freq, s1);
		frequency(freq, s2);
		frequency(freq, s3);
		// Count the number of repeating elements
		for (i = 0; i < 26; i++)
		{
			if (freq[i] > 0)
			{
				// When element occurrences
				count++;
			}
		}
		if (count > 10)
		{
			// When string are not valid
			System.out.print("Invalid string");
		}
		else
		{
			// Use to track numbers
			boolean[] use = new boolean[10];
			Node[] result = new Node[count];
			for (i = 0; i < count; i++)
			{
				result[i] = new Node();
			}
			for (i = 0, j = 0; i < 26; i++)
			{
				if (freq[i] > 0)
				{
					// Set node value
					result[j].letter = (char)(i + 'A');
					result[j].value = 0;
					// visit to next node
					j++;
				}
			}
			// Set initial values
			for (i = 0; i < count; ++i)
			{
				// Here zero indicate empty slot
				use[i] = false;
			}
			if (permutation(count, use, result, 0, s1, s2, s3) == true)
			{
				System.out.print(" Given : " + s1 + " " + s2 + " " + s3 + " \n");
				System.out.print(" Solution \n");
				// Display solution
				for (j = 0; j < count; j++)
				{
					System.out.print(" " + result[j].letter + " = " + result[j].value);
				}
			}
			else
			{
				// When no solution
				System.out.print("No Result");
			}
		}
	}
	public static void main(String[] args)
	{
		Puzzle task = new Puzzle();
		String s1 = "SUN";
		String s2 = "RUN";
		String s3 = "FAST";
		// Test
		task.cryptarithmeticPuzzle(s1, s2, s3);
	}
}

Output

 Given : SUN RUN FAST
 Solution
 A = 0 F = 1 N = 2 R = 3 S = 6 T = 4 U = 8
// Include header file
#include <iostream>

#include<string.h>

using namespace std;
/*
    C++ Program for
    Cryptarithmetic puzzle
*/
// Define node which is contain letter and resultant value
class Node
{
	public: 
    char letter;
	int value;
	Node()
	{
		this->letter = ' ';
		this->value = 0;
	}
};;
// Binary Tree
class Puzzle
{
	public: bool isValid(Node result[], int count, string s1, string s2, string s3)
	{
		int v1 = 0;
		int v2 = 0;
		int v3 = 0;
		// Loop controlling variables
		int i = 0;
		int j = 0;
		int multiplier = 1;
		for (i = s1.size() - 1; i >= 0; i--)
		{
			j = 0;
			while (j < count && result[j].letter != s1[i])
			{
				j++;
			}
			v1 = v1 + multiplier *result[j].value;
			multiplier *= 10;
		}
		multiplier = 1;
		for (i = s2.size() - 1; i >= 0; i--)
		{
			j = 0;
			while (j < count && result[j].letter != s2[i])
			{
				j++;
			}
			v2 = v2 + multiplier *result[j].value;
			multiplier *= 10;
		}
		multiplier = 1;
		for (i = s3.size() - 1; i >= 0; i--)
		{
			j = 0;
			while (j < count && result[j].letter != s3[i])
			{
				j++;
			}
			v3 = v3 + multiplier *result[j].value;
			multiplier *= 10;
		}
		if (v3 == (v1 + v2))
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	// Find solution
	bool permutation(int count, bool use[], Node result[], int n, string s1, string s2, string s3)
	{
		// Loop controlling variables
		int i = 0;
		int j = 0;
		if (n == count - 1)
		{
			for (i = 0; i < 10; i++)
			{
				if (use[i] == false)
				{
					result[n].value = i;
					if (this->isValid(result, count, s1, s2, s3) == true)
					{
						return true;
					}
				}
			}
			return false;
		}
		for (i = 0; i < 10; i++)
		{
			if (use[i] == false)
			{
				result[n].value = i;
				use[i] = true;
				if (this->permutation(count, use, result, n + 1, s1, s2, s3) == true)
				{
					// When get a result
					return true;
				}
				use[i] = false;
			}
		}
		return false;
	}
	// Calculate the frequency of character
	void frequency(int freq[], string str)
	{
		int i = 0;
		int len = str.size();
		// Calculate character frequency of givens String *
		for (i = 0; i < len; i++)
		{
			freq[str[i] - 'A']++;
		}
	}
	// Cryptarithmetic handles requests to solve puzzles
	void cryptarithmeticPuzzle(string s1, string s2, string s3)
	{
		// Use to count frequency of each character
		int freq[26];
		// Use to count of unique characters
		int count = 0;
		// Loop controlling variables
		int i = 0;
		int j = 0;
		// Set initial frequency
		for (i = 0; i < 26; i++)
		{
			freq[i] = 0;
		}
		// Count frequency of each character in a given String *( form of A-Z).
		this->frequency(freq, s1);
		this->frequency(freq, s2);
		this->frequency(freq, s3);
		// Count the number of repeating elements
		for (i = 0; i < 26; i++)
		{
			if (freq[i] > 0)
			{
				// When element occurrences
				count++;
			}
		}
		if (count > 10)
		{
			// When string are not valid
			cout << "Invalid string";
		}
		else
		{
			// Use to track numbers
			bool use[10];
			Node result[count];
			
			for (i = 0, j = 0; i < 26; i++)
			{
				if (freq[i] > 0)
				{
					// visit to next node
					// Set node value
					result[j].letter = (char)(i + 'A');
					result[j].value = 0;
					j++;
				}
			}
			// Set initial values
			for (i = 0; i < count; ++i)
			{
				// Here zero indicate empty slot
				use[i] = false;
			}
			if (this->permutation(count, use, result, 0, s1, s2, s3) == true)
			{
				cout << " Given : " << s1 << " " << s2 << " " << s3 << " \n";
				cout << " Solution \n";
				// Display solution
				for (j = 0; j < count; j++)
				{
					cout << " " << result[j].letter << " = " << result[j].value;
				}
			}
			else
			{
				// When no solution
				cout << "No Result";
			}
		}
	}
};
int main()
{
	Puzzle task = Puzzle();
	string s1 = "SUN";
	string s2 = "RUN";
	string s3 = "FAST";
	// Test
	task.cryptarithmeticPuzzle(s1, s2, s3);
	return 0;
}

Output

 Given : SUN RUN FAST
 Solution
 A = 0 F = 1 N = 2 R = 3 S = 6 T = 4 U = 8
// Include namespace system
using System;
/*
    C# Program for
    Cryptarithmetic puzzle
*/
// Define node which is contain letter and resultant value
public class Node
{
	public char letter;
	public int value;
	public Node()
	{
		this.letter = ' ';
		this.value = 0;
	}
};
// Binary Tree
public class Puzzle
{
	public Boolean isValid(Node[] result, int count, String s1, String s2, String s3)
	{
		int v1 = 0;
		int v2 = 0;
		int v3 = 0;
		// Loop controlling variables
		int i = 0;
		int j = 0;
		int multiplier = 1;
		for (i = s1.Length - 1; i >= 0; i--)
		{
			j = 0;
			while (j < count && result[j].letter != s1[i])
			{
				j++;
			}
			v1 = v1 + multiplier * result[j].value;
			multiplier *= 10;
		}
		multiplier = 1;
		for (i = s2.Length - 1; i >= 0; i--)
		{
			j = 0;
			while (j < count && result[j].letter != s2[i])
			{
				j++;
			}
			v2 = v2 + multiplier * result[j].value;
			multiplier *= 10;
		}
		multiplier = 1;
		for (i = s3.Length - 1; i >= 0; i--)
		{
			j = 0;
			while (j < count && result[j].letter != s3[i])
			{
				j++;
			}
			v3 = v3 + multiplier * result[j].value;
			multiplier *= 10;
		}
		if (v3 == (v1 + v2))
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	// Find solution
	public Boolean permutation(int count, Boolean[] use, Node[] result, int n, String s1, String s2, String s3)
	{
		// Loop controlling variable
		int i = 0;
	
		if (n == count - 1)
		{
			for (i = 0; i < 10; i++)
			{
				if (use[i] == false)
				{
					result[n].value = i;
					if (isValid(result, count, s1, s2, s3) == true)
					{
						return true;
					}
				}
			}
			return false;
		}
		for (i = 0; i < 10; i++)
		{
			if (use[i] == false)
			{
				result[n].value = i;
				use[i] = true;
				if (permutation(count, use, result, n + 1, s1, s2, s3) == true)
				{
					// When get a result
					return true;
				}
				use[i] = false;
			}
		}
		return false;
	}
	// Calculate the frequency of character
	public void frequency(int[] freq, String str)
	{
		int i = 0;
		int len = str.Length;
		// Calculate character frequency of givens String *
		for (i = 0; i < len; i++)
		{
			freq[str[i] - 'A']++;
		}
	}
	// Cryptarithmetic handles requests to solve puzzles
	public void cryptarithmeticPuzzle(String s1, String s2, String s3)
	{
		// Use to count frequency of each character
		int[] freq = new int[26];
		// Use to count of unique characters
		int count = 0;
		// Loop controlling variables
		int i = 0;
		int j = 0;
		// Set initial frequency
		for (i = 0; i < 26; i++)
		{
			freq[i] = 0;
		}
		// Count frequency of each character in a given String *( form of A-Z).
		frequency(freq, s1);
		frequency(freq, s2);
		frequency(freq, s3);
		// Count the number of repeating elements
		for (i = 0; i < 26; i++)
		{
			if (freq[i] > 0)
			{
				// When element occurrences
				count++;
			}
		}
		if (count > 10)
		{
			// When string are not valid
			Console.Write("Invalid string");
		}
		else
		{
			// Use to track numbers
			Boolean[] use = new Boolean[10];
			Node[] result = new Node[count];
			for (i = 0; i < count; i++)
			{
				result[i] = new Node();
			}
			for (i = 0, j = 0; i < 26; i++)
			{
				if (freq[i] > 0)
				{
					// visit to next node
					// Set node value
					result[j].letter = (char)(i + 'A');
					result[j].value = 0;
					j++;
				}
			}
			// Set initial values
			for (i = 0; i < count; ++i)
			{
				// Here zero indicate empty slot
				use[i] = false;
			}
			if (permutation(count, use, result, 0, s1, s2, s3) == true)
			{
				Console.Write(" Given : " + s1 + " " + s2 + " " + s3 + " \n");
				Console.Write(" Solution \n");
				// Display solution
				for (j = 0; j < count; j++)
				{
					Console.Write(" " + result[j].letter + " = " + result[j].value);
				}
			}
			else
			{
				// When no solution
				Console.Write("No Result");
			}
		}
	}
	public static void Main(String[] args)
	{
		Puzzle task = new Puzzle();
		String s1 = "SUN";
		String s2 = "RUN";
		String s3 = "FAST";
		// Test
		task.cryptarithmeticPuzzle(s1, s2, s3);
	}
}

Output

 Given : SUN RUN FAST
 Solution
 A = 0 F = 1 N = 2 R = 3 S = 6 T = 4 U = 8
<?php
/*
    Php Program for
    Cryptarithmetic puzzle
*/
// Define node which is contain letter and resultant value
class Node
{
	public $letter;
	public $value;

	function __construct()
	{
		$this->letter = ' ';
		$this->value = 0;
	}
};
// Binary Tree
class Puzzle
{
	public	function isValid( & $result, $count, $s1, $s2, $s3)
	{
		$v1 = 0;
		$v2 = 0;
		$v3 = 0;
		// Loop controlling variables
		$i = 0;
		$j = 0;
		$multiplier = 1;
		for ($i = strlen($s1) - 1; $i >= 0; $i--)
		{
			$j = 0;
			while ($j < $count && $result[$j]->letter != $s1[$i])
			{
				$j++;
			}
			$v1 = $v1 + $multiplier * $result[$j]->value;
			$multiplier *= 10;
		}
		$multiplier = 1;
		for ($i = strlen($s2) - 1; $i >= 0; $i--)
		{
			$j = 0;
			while ($j < $count && $result[$j]->letter != $s2[$i])
			{
				$j++;
			}
			$v2 = $v2 + $multiplier * $result[$j]->value;
			$multiplier *= 10;
		}
		$multiplier = 1;
		for ($i = strlen($s3) - 1; $i >= 0; $i--)
		{
			$j = 0;
			while ($j < $count && $result[$j]->letter != $s3[$i])
			{
				$j++;
			}
			$v3 = $v3 + $multiplier * $result[$j]->value;
			$multiplier *= 10;
		}
		if ($v3 == ($v1 + $v2))
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	// Find solution
	public	function permutation($count, & $use, & $result, $n, $s1, $s2, $s3)
	{
		// Loop controlling variable
		$i = 0;
		if ($n == $count - 1)
		{
			for ($i = 0; $i < 10; $i++)
			{
				if ($use[$i] == false)
				{
					$result[$n]->value = $i;
					if ($this->isValid($result, $count, $s1, $s2, $s3) == true)
					{
						return true;
					}
				}
			}
			return false;
		}
		for ($i = 0; $i < 10; $i++)
		{
			if ($use[$i] == false)
			{
				$result[$n]->value = $i;
				$use[$i] = true;
				if ($this->permutation($count, $use, $result, $n + 1, $s1, $s2, $s3) == true)
				{
					// When get a result
					return true;
				}
				$use[$i] = false;
			}
		}
		return false;
	}
	// Calculate the frequency of character
	public	function frequency( & $freq, $str)
	{
		$i = 0;
		$len = strlen($str);
		// Calculate character frequency of givens String *
		for ($i = 0; $i < $len; $i++)
		{
			$freq[ord($str[$i]) - ord('A')]++;
		}
	}
	// Cryptarithmetic handles requests to solve puzzles
	public	function cryptarithmeticPuzzle($s1, $s2, $s3)
	{
		// Use to count frequency of each character
		$freq = array_fill(0, 26, 0);
		// Use to count of unique characters
		$count = 0;
		// Loop controlling variables
		$i = 0;
		$j = 0;
		// Count frequency of each character in a given String *( form of A-Z).
		$this->frequency($freq, $s1);
		$this->frequency($freq, $s2);
		$this->frequency($freq, $s3);
		// Count the number of repeating elements
		for ($i = 0; $i < 26; $i++)
		{
			if ($freq[$i] > 0)
			{
				// When element occurrences
				$count++;
			}
		}
		if ($count > 10)
		{
			// When string are not valid
			echo "Invalid string";
		}
		else
		{
			// Use to track numbers
			$use = array_fill(0, 10, false);
			$result = array_fill(0, $count, null);
			for ($i = 0; $i < $count; $i++)
			{
				$result[$i] = new Node();
			}
			for ($i = 0, $j = 0; $i < 26; $i++)
			{
				if ($freq[$i] > 0)
				{
					// visit to next node
					// Set node value
					$result[$j]->letter = chr($i + ord('A'));
					$result[$j]->value = 0;
					$j++;
				}
			}
			// Set initial values
			for ($i = 0; $i < $count; ++$i)
			{
				// Here zero indicate empty slot
				$use[$i] = false;
			}
			if ($this->permutation($count, $use, $result, 0, $s1, $s2, $s3) == true)
			{
				echo " Given : ". $s1 ." ". $s2 ." ". $s3 ." \n";
				echo " Solution \n";
				// Display solution
				for ($j = 0; $j < $count; $j++)
				{
					echo " ". $result[$j]->letter ." = ". $result[$j]->value;
				}
			}
			else
			{
				// When no solution
				echo "No Result";
			}
		}
	}
}

function main()
{
	$task = new Puzzle();
	$s1 = "SUN";
	$s2 = "RUN";
	$s3 = "FAST";
	// Test
	$task->cryptarithmeticPuzzle($s1, $s2, $s3);
}
main();

Output

 Given : SUN RUN FAST
 Solution
 A = 0 F = 1 N = 2 R = 3 S = 6 T = 4 U = 8
/*
    Node Js Program for
    Cryptarithmetic puzzle
*/
// Define node which is contain letter and resultant value
class Node
{
	constructor()
	{
		this.letter = ' ';
		this.value = 0;
	}
};
// Binary Tree
class Puzzle
{
	isValid(result, count, s1, s2, s3)
	{
		var v1 = 0;
		var v2 = 0;
		var v3 = 0;
		// Loop controlling variables
		var i = 0;
		var j = 0;
		var multiplier = 1;
		for (i = s1.length - 1; i >= 0; i--)
		{
			j = 0;
			while (j < count && result[j].letter != s1[i])
			{
				j++;
			}
			v1 = v1 + multiplier * result[j].value;
			multiplier *= 10;
		}
		multiplier = 1;
		for (i = s2.length - 1; i >= 0; i--)
		{
			j = 0;
			while (j < count && result[j].letter != s2[i])
			{
				j++;
			}
			v2 = v2 + multiplier * result[j].value;
			multiplier *= 10;
		}
		multiplier = 1;
		for (i = s3.length - 1; i >= 0; i--)
		{
			j = 0;
			while (j < count && result[j].letter != s3[i])
			{
				j++;
			}
			v3 = v3 + multiplier * result[j].value;
			multiplier *= 10;
		}
		if (v3 == (v1 + v2))
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	// Find solution
	permutation(count, use, result, n, s1, s2, s3)
	{
		// Loop controlling variable
		var i = 0;
		if (n == count - 1)
		{
			for (i = 0; i < 10; i++)
			{
				if (use[i] == false)
				{
					result[n].value = i;
					if (this.isValid(result, count, s1, s2, s3) == true)
					{
						return true;
					}
				}
			}
			return false;
		}
		for (i = 0; i < 10; i++)
		{
			if (use[i] == false)
			{
				result[n].value = i;
				use[i] = true;
				if (this.permutation(count, use, result, n + 1, s1, s2, s3) == true)
				{
					// When get a result
					return true;
				}
				use[i] = false;
			}
		}
		return false;
	}
	// Calculate the frequency of character
	frequency(freq, str)
	{
		var i = 0;
		var len = str.length;
		// Calculate character frequency of givens String *
		for (i = 0; i < len; i++)
		{
			freq[(str[i]).charCodeAt(0) - ('A').charCodeAt(0)]++;
		}
	}
	// Cryptarithmetic handles requests to solve puzzles
	cryptarithmeticPuzzle(s1, s2, s3)
	{
		// Use to count frequency of each character
		var freq = Array(26).fill(0);
		// Use to count of unique characters
		var count = 0;
		// Loop controlling variables
		var i = 0;
		var j = 0;
		// Count frequency of each character in a given String *( form of A-Z).
		this.frequency(freq, s1);
		this.frequency(freq, s2);
		this.frequency(freq, s3);
		// Count the number of repeating elements
		for (i = 0; i < 26; i++)
		{
			if (freq[i] > 0)
			{
				// When element occurrences
				count++;
			}
		}
		if (count > 10)
		{
			// When string are not valid
			process.stdout.write("Invalid string");
		}
		else
		{
			// Use to track numbers
			var use = Array(10).fill(false);
			var result = Array(count).fill(null);
			for (i = 0; i < count; i++)
			{
				result[i] = new Node();
			}
			for (i = 0, j = 0; i < 26; i++)
			{
				if (freq[i] > 0)
				{
					// visit to next node
					// Set node value
					result[j].letter = String.fromCharCode((i + ('A').charCodeAt(0)));
					result[j].value = 0;
					j++;
				}
			}
			// Set initial values
			for (i = 0; i < count; ++i)
			{
				// Here zero indicate empty slot
				use[i] = false;
			}
			if (this.permutation(count, use, result, 0, s1, s2, s3) == true)
			{
				process.stdout.write(" Given : " + s1 + " " + s2 + " " + s3 + " \n");
				process.stdout.write(" Solution \n");
				// Display solution
				for (j = 0; j < count; j++)
				{
					process.stdout.write(" " + result[j].letter + " = " + result[j].value);
				}
			}
			else
			{
				// When no solution
				process.stdout.write("No Result");
			}
		}
	}
}

function main()
{
	var task = new Puzzle();
	var s1 = "SUN";
	var s2 = "RUN";
	var s3 = "FAST";
	// Test
	task.cryptarithmeticPuzzle(s1, s2, s3);
}
main();

Output

 Given : SUN RUN FAST
 Solution
 A = 0 F = 1 N = 2 R = 3 S = 6 T = 4 U = 8
#   Python 3 Program for
#   Cryptarithmetic puzzle

#  Define node which is contain letter and resultant value
class Node :
	
	def __init__(self) :
		self.letter = ' '
		self.value = 0
	

#  Binary Tree
class Puzzle :
	def isValid(self, result, count, s1, s2, s3) :
		v1 = 0
		v2 = 0
		v3 = 0
		#  Loop controlling variables
		i = 0
		j = 0
		multiplier = 1
		i = len(s1) - 1
		while (i >= 0) :
			j = 0
			while (j < count and result[j].letter != s1[i]) :
				j += 1
			
			v1 = v1 + multiplier * result[j].value
			multiplier *= 10
			i -= 1
		
		multiplier = 1
		i = len(s2) - 1
		while (i >= 0) :
			j = 0
			while (j < count and result[j].letter != s2[i]) :
				j += 1
			
			v2 = v2 + multiplier * result[j].value
			multiplier *= 10
			i -= 1
		
		multiplier = 1
		i = len(s3) - 1
		while (i >= 0) :
			j = 0
			while (j < count and result[j].letter != s3[i]) :
				j += 1
			
			v3 = v3 + multiplier * result[j].value
			multiplier *= 10
			i -= 1
		
		if (v3 == (v1 + v2)) :
			return True
		else :
			return False
		
	
	#  Find solution
	def permutation(self, count, use, result, n, s1, s2, s3) :
		#  Loop controlling variable
		i = 0
		if (n == count - 1) :
			i = 0
			while (i < 10) :
				if (use[i] == False) :
					result[n].value = i
					if (self.isValid(result, count, s1, s2, s3) == True) :
						return True
					
				
				i += 1
			
			return False
		
		i = 0
		while (i < 10) :
			if (use[i] == False) :
				result[n].value = i
				use[i] = True
				if (self.permutation(count, use, result, n + 1, s1, s2, s3) == True) :
					#  When get a result
					return True
				
				use[i] = False
			
			i += 1
		
		return False
	
	#  Calculate the frequency of character
	def frequency(self, freq, str) :
		i = 0
		size = len(str)
		#  Calculate character frequency of givens String *
		i = 0
		while (i < size) :
			freq[ord(str[i]) - ord('A')] += 1
			i += 1
		
	
	#  Cryptarithmetic handles requests to solve puzzles
	def cryptarithmeticPuzzle(self, s1, s2, s3) :
		#  Use to count frequency of each character
		freq = [0] * (26)
		#  Use to count of unique characters
		count = 0
		#  Loop controlling variables
		i = 0
		j = 0
		#  Count frequency of each character in a given String *( form of A-Z).
		self.frequency(freq, s1)
		self.frequency(freq, s2)
		self.frequency(freq, s3)
		#  Count the number of repeating elements
		i = 0
		while (i < 26) :
			if (freq[i] > 0) :
				#  When element occurrences
				count += 1
			
			i += 1
		
		if (count > 10) :
			#  When string are not valid
			print("Invalid string", end = "")
		else :
			#  Use to track numbers
			use = [False] * (10)
			result = [None] * (count)
			i = 0
			while (i < count) :
				result[i] = Node()
				i += 1
			
			i = 0
			j = 0
			while (i < 26) :
				if (freq[i] > 0) :
					#  visit to next node
					#  Set node value
					result[j].letter = chr((i + ord('A')))
					result[j].value = 0
					j += 1
				
				i += 1
			
			#  Set initial values
			i = 0
			while (i < count) :
				#  Here zero indicate empty slot
				use[i] = False
				i += 1
			
			if (self.permutation(count, use, result, 0, s1, s2, s3) == True) :
				print(" Given : ", s1 ," ", s2 ," ", s3 ," ")
				print(" Solution ")
				#  Display solution
				j = 0
				while (j < count) :
					print(" ", result[j].letter ," = ", result[j].value, end = "")
					j += 1
				
			else :
				#  When no solution
				print("No Result", end = "")
			
		
	

def main() :
	task = Puzzle()
	s1 = "SUN"
	s2 = "RUN"
	s3 = "FAST"
	#  Test
	task.cryptarithmeticPuzzle(s1, s2, s3)

if __name__ == "__main__": main()

Output

 Given :  SUN   RUN   FAST
 Solution
  A  =  0  F  =  1  N  =  2  R  =  3  S  =  6  T  =  4  U  =  8
#  Ruby Program for
#  Cryptarithmetic puzzle

#  Define node which is contain letter and resultant value
class Node  
	# Define the accessor and reader of class Node  
	attr_reader :letter, :value
	attr_accessor :letter, :value
 
	
	def initialize() 
		self.letter = ' '
		self.value = 0
	end

end

#  Binary Tree
class Puzzle 
	def isValid(result, count, s1, s2, s3) 
		v1 = 0
		v2 = 0
		v3 = 0
		#  Loop controlling variables
		i = 0
		j = 0
		multiplier = 1
		i = s1.length() - 1
		while (i >= 0) 
			j = 0
			while (j < count && result[j].letter != s1[i]) 
				j += 1
			end

			v1 = v1 + multiplier * result[j].value
			multiplier *= 10
			i -= 1
		end

		multiplier = 1
		i = s2.length() - 1
		while (i >= 0) 
			j = 0
			while (j < count && result[j].letter != s2[i]) 
				j += 1
			end

			v2 = v2 + multiplier * result[j].value
			multiplier *= 10
			i -= 1
		end

		multiplier = 1
		i = s3.length() - 1
		while (i >= 0) 
			j = 0
			while (j < count && result[j].letter != s3[i]) 
				j += 1
			end

			v3 = v3 + multiplier * result[j].value
			multiplier *= 10
			i -= 1
		end

		if (v3 == (v1 + v2)) 
			return true
		else 
			return false
		end

	end

	#  Find solution
	def permutation(count, use, result, n, s1, s2, s3) 
		#  Loop controlling variable
		i = 0
		if (n == count - 1) 
			i = 0
			while (i < 10) 
				if (use[i] == false) 
					result[n].value = i
					if (self.isValid(result, count, s1, s2, s3) == true) 
						return true
					end

				end

				i += 1
			end

			return false
		end

		i = 0
		while (i < 10) 
			if (use[i] == false) 
				result[n].value = i
				use[i] = true
				if (self.permutation(count, use, result, n + 1, s1, s2, s3) == true) 
					#  When get a result
					return true
				end

				use[i] = false
			end

			i += 1
		end

		return false
	end

	#  Calculate the frequency of character
	def frequency(freq, str) 
		i = 0
		len = str.length()
		#  Calculate character frequency of givens String *
		i = 0
		while (i < len) 
			freq[(str[i]).ord - ('A').ord] += 1
			i += 1
		end

	end

	#  Cryptarithmetic handles requests to solve puzzles
	def cryptarithmeticPuzzle(s1, s2, s3) 
		#  Use to count frequency of each character
		freq = Array.new(26) {0}
		#  Use to count of unique characters
		count = 0
		#  Loop controlling variables
		i = 0
		j = 0
		#  Count frequency of each character in a given String *( form of A-Z).
		self.frequency(freq, s1)
		self.frequency(freq, s2)
		self.frequency(freq, s3)
		#  Count the number of repeating elements
		i = 0
		while (i < 26) 
			if (freq[i] > 0) 
				#  When element occurrences
				count += 1
			end

			i += 1
		end

		if (count > 10) 
			#  When string are not valid
			print("Invalid string")
		else 
			#  Use to track numbers
			use = Array.new(10) {false}
			result = Array.new(count) {nil}
			i = 0
			while (i < count) 
				result[i] = Node.new()
				i += 1
			end

			i = 0
			j = 0
			while (i < 26) 
				if (freq[i] > 0) 
					#  visit to next node
					#  Set node value
					result[j].letter = ((i + ('A').ord)).chr
					result[j].value = 0
					j += 1
				end

				i += 1
			end

			#  Set initial values
			i = 0
			while (i < count) 
				#  Here zero indicate empty slot
				use[i] = false
				i += 1
			end

			if (self.permutation(count, use, result, 0, s1, s2, s3) == true) 
				print(" Given : ", s1 ," ", s2 ," ", s3 ," \n")
				print(" Solution \n")
				#  Display solution
				j = 0
				while (j < count) 
					print(" ", result[j].letter ," = ", result[j].value)
					j += 1
				end

			else 
				#  When no solution
				print("No Result")
			end

		end

	end

end

def main() 
	task = Puzzle.new()
	s1 = "SUN"
	s2 = "RUN"
	s3 = "FAST"
	#  Test
	task.cryptarithmeticPuzzle(s1, s2, s3)
end

main()

Output

 Given : SUN RUN FAST 
 Solution 
 A = 0 F = 1 N = 2 R = 3 S = 6 T = 4 U = 8
/*
    Scala Program for
    Cryptarithmetic puzzle
*/
// Define node which is contain letter and resultant value
class Node(var letter: Character , var value: Int)
{
	def this()
	{
		this(' ', 0);
	}
};
// Binary Tree
class Puzzle
{
	def isValid(result: Array[Node], count: Int, s1: String, s2: String, s3: String): Boolean = {
		var v1: Int = 0;
		var v2: Int = 0;
		var v3: Int = 0;
		// Loop controlling variables
		var i: Int = 0;
		var j: Int = 0;
		var multiplier: Int = 1;
		i = s1.length() - 1;
		while (i >= 0)
		{
			j = 0;
			while (j < count && result(j).letter != s1(i))
			{
				j += 1;
			}
			v1 = v1 + multiplier * result(j).value;
			multiplier *= 10;
			i -= 1;
		}
		multiplier = 1;
		i = s2.length() - 1;
		while (i >= 0)
		{
			j = 0;
			while (j < count && result(j).letter != s2(i))
			{
				j += 1;
			}
			v2 = v2 + multiplier * result(j).value;
			multiplier *= 10;
			i -= 1;
		}
		multiplier = 1;
		i = s3.length() - 1;
		while (i >= 0)
		{
			j = 0;
			while (j < count && result(j).letter != s3(i))
			{
				j += 1;
			}
			v3 = v3 + multiplier * result(j).value;
			multiplier *= 10;
			i -= 1;
		}
		if (v3 == (v1 + v2))
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	// Find solution
	def permutation(count: Int, use: Array[Boolean], result: Array[Node], n: Int, s1: String, s2: String, s3: String): Boolean = {
		// Loop controlling variable
		var i: Int = 0;
		if (n == count - 1)
		{
			i = 0;
			while (i < 10)
			{
				if (use(i) == false)
				{
					result(n).value = i;
					if (this.isValid(result, count, s1, s2, s3) == true)
					{
						return true;
					}
				}
				i += 1;
			}
			return false;
		}
		i = 0;
		while (i < 10)
		{
			if (use(i) == false)
			{
				result(n).value = i;
				use(i) = true;
				if (this.permutation(count, use, result, n + 1, s1, s2, s3) == true)
				{
					// When get a result
					return true;
				}
				use(i) = false;
			}
			i += 1;
		}
		return false;
	}
	// Calculate the frequency of character
	def frequency(freq: Array[Int], str: String): Unit = {
		var i: Int = 0;
		var len: Int = str.length();
		// Calculate character frequency of givens String *
		i = 0;
		while (i < len)
		{
			freq(str(i) - 'A') += 1;
			i += 1;
		}
	}
	// Cryptarithmetic handles requests to solve puzzles
	def cryptarithmeticPuzzle(s1: String, s2: String, s3: String): Unit = {
		// Use to count frequency of each character
		var freq: Array[Int] = Array.fill[Int](26)(0);
		// Use to count of unique characters
		var count: Int = 0;
		// Loop controlling variables
		var i: Int = 0;
		var j: Int = 0;
		// Count frequency of each character in a given String *( form of A-Z).
		this.frequency(freq, s1);
		this.frequency(freq, s2);
		this.frequency(freq, s3);
		// Count the number of repeating elements
		i = 0;
		while (i < 26)
		{
			if (freq(i) > 0)
			{
				// When element occurrences
				count += 1;
			}
			i += 1;
		}
		if (count > 10)
		{
			// When string are not valid
			print("Invalid string");
		}
		else
		{
			// Use to track numbers
			var use: Array[Boolean] = Array.fill[Boolean](10)(false);
			var result: Array[Node] = Array.fill[Node](count)(null);
			i = 0;
			while (i < count)
			{
				result(i) = new Node();
				i += 1;
			}
			i = 0;
			j = 0;
			while (i < 26)
			{
				if (freq(i) > 0)
				{
					// visit to next node
					// Set node value
					result(j).letter = ((i + 'A')).toChar;
					result(j).value = 0;
					j += 1;
				}
				i += 1;
			}
			// Set initial values
			i = 0;
			while (i < count)
			{
				// Here zero indicate empty slot
				use(i) = false;
				i += 1;
			}
			if (this.permutation(count, use, result, 0, s1, s2, s3) == true)
			{
				print(" Given : " + s1 + " " + s2 + " " + s3 + " \n");
				print(" Solution \n");
				// Display solution
				j = 0;
				while (j < count)
				{
					print(" " + result(j).letter + " = " + result(j).value);
					j += 1;
				}
			}
			else
			{
				// When no solution
				print("No Result");
			}
		}
	}
}
object Main
{
	def main(args: Array[String]): Unit = {
		var task: Puzzle = new Puzzle();
		var s1: String = "SUN";
		var s2: String = "RUN";
		var s3: String = "FAST";
		// Test
		task.cryptarithmeticPuzzle(s1, s2, s3);
	}
}

Output

 Given : SUN RUN FAST
 Solution
 A = 0 F = 1 N = 2 R = 3 S = 6 T = 4 U = 8
/*
    Swift 4 Program for
    Cryptarithmetic puzzle
*/
// Define node which is contain letter and resultant value
class Node
{
	var letter: Character;
	var value: Int;
	init()
	{
		self.letter = " ";
		self.value = 0;
	}
};
// Binary Tree
class Puzzle
{
	func isValid(_ result: [Node?], _ count: Int, _ a1: String, _ a2: String, _ a3: String)->Bool
	{
		var v1: Int = 0;
		var v2: Int = 0;
		var v3: Int = 0;
		// Loop controlling variables
		var i: Int = 0;
		var j: Int = 0;
		var multiplier: Int = 1;
		i = a1.count - 1;
      	let s1 = Array(a1);
      	let s2 = Array(a2);
      	let s3 = Array(a3);
		while (i >= 0)
		{
			j = 0;
			while (j < count && result[j]!.letter  != s1[i])
			{
				j += 1;
			}
			v1 = v1 + multiplier * result[j]!.value;
			multiplier *= 10;
			i -= 1;
		}
		multiplier = 1;
		i = a2.count - 1;
		while (i >= 0)
		{
			j = 0;
			while (j < count && result[j]!.letter != s2[i])
			{
				j += 1;
			}
			v2 = v2 + multiplier * result[j]!.value;
			multiplier *= 10;
			i -= 1;
		}
		multiplier = 1;
		i = a3.count - 1;
		while (i >= 0)
		{
			j = 0;
			while (j < count && result[j]!.letter  != s3[i])
			{
				j += 1;
			}
			v3 = v3 + multiplier * result[j]!.value;
			multiplier *= 10;
			i -= 1;
		}
		if (v3 == (v1 + v2))
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	// Find solution
	func permutation(_ count: Int, _ use: inout[Bool], _ result: [Node? ], _ n: Int, _ s1: String, _ s2: String, _ s3: String)->Bool
	{
		// Loop controlling variable
		var i: Int = 0;
		if (n == count - 1)
		{
			i = 0;
			while (i < 10)
			{
				if (use[i] == false)
				{
					result[n]!.value = i;
					if (self.isValid(result, count, s1, s2, s3) == true)
					{
						return true;
					}
				}
				i += 1;
			}
			return false;
		}
		i = 0;
		while (i < 10)
		{
			if (use[i] == false)
			{
				result[n]!.value = i;
				use[i] = true;
				if (self.permutation(count, &use, result, n + 1, s1, s2, s3) == true)
				{
					// When get a result
					return true;
				}
				use[i] = false;
			}
			i += 1;
		}
		return false;
	}
	// Calculate the frequency of character
	func frequency(_ freq: inout[Int], _ s: String)
	{
		var i: Int = 0;
		let len: Int = s.count;
      	let str = Array(s);
      	var index = 0;
		// Calculate character frequency of givens String *
	
      
		while (i < len)
		{
          	index = Int(UnicodeScalar(String(str[i]))!.value  - UnicodeScalar("A")!.value);
			freq[index] += 1;
			i += 1;
		}
	}
	// Cryptarithmetic handles requests to solve puzzles
	func cryptarithmeticPuzzle(_ s1: String, _ s2: String, _ s3: String)
	{
		// Use to count frequency of each character
		var freq: [Int] = Array(repeating: 0, count: 26);
		// Use to count of unique characters
		var count: Int = 0;
		// Loop controlling variables
		var i: Int = 0;
		var j: Int = 0;
		// Count frequency of each character in a given String *( form of A-Z).
		self.frequency(&freq, s1);
		self.frequency(&freq, s2);
		self.frequency(&freq, s3);
		// Count the number of repeating elements
		i = 0;
		while (i < 26)
		{
			if (freq[i] > 0)
			{
				// When element occurrences
				count += 1;
			}
			i += 1;
		}
		if (count > 10)
		{
			// When string are not valid
			print("Invalid string", terminator: "");
		}
		else
		{
			// Use to track numbers
			var use: [Bool] = Array(repeating: false, count: 10);
			var result: [Node? ] = Array(repeating: nil, count: count);
			i = 0;
			while (i < count)
			{
				result[i] = Node();
				i += 1;
			}
			i = 0;
			j = 0;
			while (i < 26)
			{
				if (freq[i] > 0)
				{
					// visit to next node
					// Set node value
					result[j]!.letter = Character(UnicodeScalar(UInt8((i + Int(UnicodeScalar("A")!.value)))));
					result[j]!.value = 0;
					j += 1;
				}
				i += 1;
			}
			// Set initial values
			i = 0;
			while (i < count)
			{
				// Here zero indicate empty slot
				use[i] = false;
				i += 1;
			}
			if (self.permutation(count, &use, result, 0, s1, s2, s3) == true)
			{
				print(" Given : ", s1 ," ", s2 ," ", s3 ," ");
				print(" Solution ");
				// Display solution
				j = 0;
				while (j < count)
				{
					print(" ", result[j]!.letter ," = ", result[j]!.value, terminator: "");
					j += 1;
				}
			}
			else
			{
				// When no solution
				print("No Result", terminator: "");
			}
		}
	}
}
func main()
{
	let task: Puzzle = Puzzle();
	let s1: String = "SUN";
	let s2: String = "RUN";
	let s3: String = "FAST";
	// Test
	task.cryptarithmeticPuzzle(s1, s2, s3);
}
main();

Output

 Given :  SUN   RUN   FAST
 Solution
  A  =  0  F  =  1  N  =  2  R  =  3  S  =  6  T  =  4  U  =  8
/*
    Kotlin Program for
    Cryptarithmetic puzzle
*/
// Define node which is contain letter and resultant value
class Node
{
    var letter: Char;
    var value: Int;
    constructor()
    {
        this.letter = ' ';
        this.value = 0;
    }
};
// Binary Tree
class Puzzle
{
    fun isValid(result: Array<Node?> , count : Int, s1: String, s2: String, s3: String): Boolean
    {
        var v1: Int = 0;
        var v2: Int = 0;
        var v3: Int = 0;
        // Loop controlling variables
        var i: Int ;
        var j: Int ;
        var multiplier: Int = 1;
        i = s1.count() - 1;
        while (i >= 0)
        {
            j = 0;
            while (j < count && result[j]!!.letter != s1[i])
            {
                j += 1;
            }
            v1 = v1 + multiplier * result[j]!!.value;
            multiplier *= 10;
            i -= 1;
        }
        multiplier = 1;
        i = s2.count() - 1;
        while (i >= 0)
        {
            j = 0;
            while (j < count && result[j]!!.letter != s2[i])
            {
                j += 1;
            }
            v2 = v2 + multiplier * result[j]!!.value;
            multiplier *= 10;
            i -= 1;
        }
        multiplier = 1;
        i = s3.count() - 1;
        while (i >= 0)
        {
            j = 0;
            while (j < count && result[j]!!.letter != s3[i])
            {
                j += 1;
            }
            v3 = v3 + multiplier * result[j]!!.value;
            multiplier *= 10;
            i -= 1;
        }
        if (v3 == (v1 + v2))
        {
            return true;
        }
        else
        {
            return false;
        }
    }
    // Find solution
    fun permutation(count: Int, use: Array <Boolean> , result: Array <Node?> , n : Int, s1: String, s2: String, s3: String): Boolean
    {
        // Loop controlling variable
        var i: Int = 0;
        if (n == count - 1)
        {
            while (i < 10)
            {
                if (use[i] == false)
                {
                    result[n]!!.value = i;
                    if (this.isValid(result, count, s1, s2, s3) == true)
                    {
                        return true;
                    }
                }
                i += 1;
            }
            return false;
        }
        while (i < 10)
        {
            if (use[i] == false)
            {
                result[n]!!.value = i;
                use[i] = true;
                if (this.permutation(count, use, result, n + 1, s1, s2, s3) == true)
                {
                    // When get a result
                    return true;
                }
                use[i] = false;
            }
            i += 1;
        }
        return false;
    }
    // Calculate the frequency of character
    fun frequency(freq: Array <Int> , str: String): Unit
    {
        var i: Int = 0;
        var len: Int = str.count();
        // Calculate character frequency of givens String *
        while (i < len)
        {
            freq[str[i] - 'A'] += 1;
            i += 1;
        }
    }
    // Cryptarithmetic handles requests to solve puzzles
    fun cryptarithmeticPuzzle(s1: String, s2: String, s3: String): Unit
    {
        // Use to count frequency of each character
        var freq: Array <Int> = Array(26){0};
        // Use to count of unique characters
        var count: Int = 0;
        // Loop controlling variables
        var i: Int = 0;
        var j: Int = 0;
        // Count frequency of each character in a given String *( form of A-Z).
        this.frequency(freq, s1);
        this.frequency(freq, s2);
        this.frequency(freq, s3);
        // Count the number of repeating elements
        while (i < 26)
        {
            if (freq[i] > 0)
            {
                // When element occurrences
                count += 1;
            }
            i += 1;
        }
        if (count > 10)
        {
            // When string are not valid
            print("Invalid string");
        }
        else
        {
            // Use to track numbers
            var use: Array <Boolean> = Array(10){false};
            var result: Array <Node?> = Array(count){null};
            i = 0;
            while (i < count)
            {
                result[i] = Node();
                i += 1;
            }
            i = 0;
            while (i < 26)
            {
                if (freq[i] > 0)
                {
                    // visit to next node
                    // Set node value
                    result[j]!!.letter = (i + 'A'.toInt()).toChar();
                    result[j]!!.value = 0;
                    j += 1;
                }
                i += 1;
            }
            // Set initial values
            i = 0;
            while (i < count)
            {
                // Here zero indicate empty slot
                use[i] = false;
                i += 1;
            }
            if (this.permutation(count, use, result, 0, s1, s2, s3) == true)
            {
                print(" Given : " + s1 + " " + s2 + " " + s3 + " \n");
                print(" Solution \n");
                // Display solution
                j = 0;
                while (j < count)
                {
                    print(" " + result[j]!!.letter + " = " + result[j]!!.value);
                    j += 1;
                }
            }
            else
            {
                // When no solution
                print("No Result");
            }
        }
    }
}
fun main(args: Array < String > ): Unit
{
    var task: Puzzle = Puzzle();
    var s1: String = "SUN";
    var s2: String = "RUN";
    var s3: String = "FAST";
    // Test
    task.cryptarithmeticPuzzle(s1, s2, s3);
}

Output

 Given : SUN RUN FAST
 Solution
 A = 0 F = 1 N = 2 R = 3 S = 6 T = 4 U = 8
Last updated on by Kalkicode




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