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Remove repeated digits in a given number

Given an integer number, the task is to remove any consecutive repeated digits from it and return the modified number. If the number is negative, the sign should be retained in the output. For instance, if the input number is -123300, the output should be -1230.

Example

Let's consider an example to understand the problem better:

Input: 1134332

Output: 13432

Pseudocode

Procedure removeRecurring(x):
    num = x
    if x < 0:
        num = -num
    back = num % 10
    current = 0
    ans = back
    mul = 10
    num = num / 10
    while num > 0:
        current = num % 10
        if current != back:
            ans = (current * mul) + ans
            back = current
            mul *= 10
        num /= 10
    if x < 0:
        ans = -ans
    Display "Given number:", x
    Display "Output:", ans

Algorithm Explanation

The algorithm takes an input integer x and initializes a variable num with the absolute value of x. If x is negative, num will hold its positive counterpart. The algorithm then extracts the last digit of num and stores it in back. This digit will serve as a reference for comparison.

The algorithm also initializes the variable ans with the last digit, as the final result will be constructed digit by digit. The variable mul is initialized with 10, which will be used to position the current digit properly in the final result.

Next, the algorithm starts a loop to iterate through the remaining digits of num (excluding the last digit already stored in back). In each iteration, it extracts the next digit, current, and compares it with back. If current is different from back, it means a new digit has been found, and it needs to be added to the result. The algorithm places current at the beginning of ans and updates back to the value of current. It also adjusts the value of mul for the next digit position.

This process continues until all digits have been processed. After the loop ends, the algorithm checks if the original input x was negative. If so, it makes ans negative as well to match the sign of the input.

Finally, the algorithm displays the original input x and the modified number ans as the output.

Code Solution

Here given code implementation process.

/*
  C Program for
  Remove repeated digits in a given number
*/
#include <stdio.h>

// Remove recurring digits in a given number
void removeRecurring(int x)
{
	int num = x;
	if (x < 0)
	{
		// When given number is negative
		num = -num;
	}
	// Define some auxiliary variables
	int back = num % 10;
	int current = 0;
	int ans = back;
	int mul = 10;
	num = num / 10;
	while (num > 0)
	{
		current = num % 10;
		if (current != back)
		{
			// Add current digit at beginning of result
			ans = (current *mul) + ans;
			back = current;
			mul *= 10;
		}
		// reduce number
		num /= 10;
	}
	if (x < 0)
	{
		ans = -ans;
	}
	// Display result
	printf("\n Given number : %d", x);
	printf("\n Output       : %d", ans);
}
int main()
{
	// Test
	removeRecurring(1134332);
	removeRecurring(-123300);
	return 0;
}

Output

 Given number : 1134332
 Output       : 13432
 Given number : -123300
 Output       : -1230
/*
  Java Program for
  Remove repeated digits in a given number
*/
class Recurring
{
	// Remove recurring digits in a given number
	public void removeRecurring(int x)
	{
		int num = x;
		if (x < 0)
		{
			// When given number is negative
			num = -num;
		}
		// Define some auxiliary variables
		int back = num % 10;
		int current = 0;
		int ans = back;
		int mul = 10;
		num = num / 10;
		while (num > 0)
		{
			current = num % 10;
			if (current != back)
			{
				// Add current digit at beginning of result
				ans = (current * mul) + ans;
				back = current;
				mul *= 10;
			}
			// reduce number
			num /= 10;
		}
		if (x < 0)
		{
			ans = -ans;
		}
		// Display result
		System.out.print("\n Given number : " + x);
		System.out.print("\n Output : " + ans);
	}
	public static void main(String[] args)
	{
		Recurring task = new Recurring();
		// Test
		task.removeRecurring(1134332);
		task.removeRecurring(-123300);
	}
}

Output

 Given number : 1134332
 Output : 13432
 Given number : -123300
 Output : -1230
// Include header file
#include <iostream>

using namespace std;
/*
  C++ Program for
  Remove repeated digits in a given number
*/
class Recurring
{
	public:
		// Remove recurring digits in a given number
		void removeRecurring(int x)
		{
			int num = x;
			if (x < 0)
			{
				// When given number is negative
				num = -num;
			}
			// Define some auxiliary variables
			int back = num % 10;
			int current = 0;
			int ans = back;
			int mul = 10;
			num = num / 10;
			while (num > 0)
			{
				current = num % 10;
				if (current != back)
				{
					// Add current digit at beginning of result
					ans = (current *mul) + ans;
					back = current;
					mul *= 10;
				}
				// reduce number
				num /= 10;
			}
			if (x < 0)
			{
				ans = -ans;
			}
			// Display result
			cout << "\n Given number : " << x;
			cout << "\n Output : " << ans;
		}
};
int main()
{
	Recurring task = Recurring();
	// Test
	task.removeRecurring(1134332);
	task.removeRecurring(-123300);
	return 0;
}

Output

 Given number : 1134332
 Output : 13432
 Given number : -123300
 Output : -1230
// Include namespace system
using System;
/*
  C# Program for
  Remove repeated digits in a given number
*/
public class Recurring
{
	// Remove recurring digits in a given number
	public void removeRecurring(int x)
	{
		int num = x;
		if (x < 0)
		{
			// When given number is negative
			num = -num;
		}
		// Define some auxiliary variables
		int back = num % 10;
		int current = 0;
		int ans = back;
		int mul = 10;
		num = num / 10;
		while (num > 0)
		{
			current = num % 10;
			if (current != back)
			{
				// Add current digit at beginning of result
				ans = (current * mul) + ans;
				back = current;
				mul *= 10;
			}
			// reduce number
			num /= 10;
		}
		if (x < 0)
		{
			ans = -ans;
		}
		// Display result
		Console.Write("\n Given number : " + x);
		Console.Write("\n Output : " + ans);
	}
	public static void Main(String[] args)
	{
		Recurring task = new Recurring();
		// Test
		task.removeRecurring(1134332);
		task.removeRecurring(-123300);
	}
}

Output

 Given number : 1134332
 Output : 13432
 Given number : -123300
 Output : -1230
<?php
/*
  Php Program for
  Remove repeated digits in a given number
*/
class Recurring
{
	// Remove recurring digits in a given number
	public	function removeRecurring($x)
	{
		$num = $x;
		if ($x < 0)
		{
			// When given number is negative
			$num = -$num;
		}
		// Define some auxiliary variables
		$back = $num % 10;
		$current = 0;
		$ans = $back;
		$mul = 10;
		$num = intval($num / 10);
		while ($num > 0)
		{
			$current = $num % 10;
			if ($current != $back)
			{
				// Add current digit at beginning of result
				$ans = ($current * $mul) + $ans;
				$back = $current;
				$mul *= 10;
			}
			// reduce number
			$num = intval($num / 10);
		}
		if ($x < 0)
		{
			$ans = -$ans;
		}
		// Display result
		echo "\n Given number : ". $x;
		echo "\n Output : ". $ans;
	}
}

function main()
{
	$task = new Recurring();
	// Test
	$task->removeRecurring(1134332);
	$task->removeRecurring(-123300);
}
main();

Output

 Given number : 1134332
 Output : 13432
 Given number : -123300
 Output : -1230
/*
  Node Js Program for
  Remove repeated digits in a given number
*/
class Recurring
{
	// Remove recurring digits in a given number
	removeRecurring(x)
	{
		var num = x;
		if (x < 0)
		{
			// When given number is negative
			num = -num;
		}
		// Define some auxiliary variables
		var back = num % 10;
		var current = 0;
		var ans = back;
		var mul = 10;
		num = parseInt(num / 10);
		while (num > 0)
		{
			current = num % 10;
			if (current != back)
			{
				// Add current digit at beginning of result
				ans = (current * mul) + ans;
				back = current;
				mul *= 10;
			}
			// reduce number
			num = parseInt(num / 10);
		}
		if (x < 0)
		{
			ans = -ans;
		}
		// Display result
		process.stdout.write("\n Given number : " + x);
		process.stdout.write("\n Output : " + ans);
	}
}

function main()
{
	var task = new Recurring();
	// Test
	task.removeRecurring(1134332);
	task.removeRecurring(-123300);
}
main();

Output

 Given number : 1134332
 Output : 13432
 Given number : -123300
 Output : -1230
#   Python 3 Program for
#   Remove repeated digits in a given number

class Recurring :
	#  Remove recurring digits in a given number
	def removeRecurring(self, x) :
		num = x
		if (x < 0) :
			#  When given number is negative
			num = -num
		
		#  Define some auxiliary variables
		back = num % 10
		current = 0
		ans = back
		mul = 10
		num = int(num / 10)
		while (num > 0) :
			current = num % 10
			if (current != back) :
				#  Add current digit at beginning of result
				ans = (current * mul) + ans
				back = current
				mul *= 10
			
			num = int(num /
				#  reduce number
				10)
		
		if (x < 0) :
			ans = -ans
		
		#  Display result
		print("\n Given number : ", x, end = "")
		print("\n Output : ", ans, end = "")
	

def main() :
	task = Recurring()
	#  Test
	task.removeRecurring(1134332)
	task.removeRecurring(-123300)

if __name__ == "__main__": main()

Output

 Given number :  1134332
 Output :  13432
 Given number :  -123300
 Output :  -1230
#   Ruby Program for
#   Remove repeated digits in a given number

class Recurring 
	#  Remove recurring digits in a given number
	def removeRecurring(x) 
		num = x
		if (x < 0) 
			#  When given number is negative
			num = -num
		end

		#  Define some auxiliary variables
		back = num % 10
		current = 0
		ans = back
		mul = 10
		num = num / 10
		while (num > 0) 
			current = num % 10
			if (current != back) 
				#  Add current digit at beginning of result
				ans = (current * mul) + ans
				back = current
				mul *= 10
			end

			#  reduce number
			num /= 10
		end

		if (x < 0) 
			ans = -ans
		end

		#  Display result
		print("\n Given number : ", x)
		print("\n Output : ", ans)
	end

end

def main() 
	task = Recurring.new()
	#  Test
	task.removeRecurring(1134332)
	task.removeRecurring(-123300)
end

main()

Output

 Given number : 1134332
 Output : 13432
 Given number : -123300
 Output : -1230
/*
  Scala Program for
  Remove repeated digits in a given number
*/
class Recurring
{
	// Remove recurring digits in a given number
	def removeRecurring(x: Int): Unit = {
		var num: Int = x;
		if (x < 0)
		{
			// When given number is negative
			num = -num;
		}
		// Define some auxiliary variables
		var back: Int = num % 10;
		var current: Int = 0;
		var ans: Int = back;
		var mul: Int = 10;
		num = (num / 10).toInt;
		while (num > 0)
		{
			current = num % 10;
			if (current != back)
			{
				// Add current digit at beginning of result
				ans = (current * mul) + ans;
				back = current;
				mul *= 10;
			}
			// reduce number
			num = (num / 10).toInt;
		}
		if (x < 0)
		{
			ans = -ans;
		}
		// Display result
		print("\n Given number : " + x);
		print("\n Output : " + ans);
	}
}
object Main
{
	def main(args: Array[String]): Unit = {
		var task: Recurring = new Recurring();
		// Test
		task.removeRecurring(1134332);
		task.removeRecurring(-123300);
	}
}

Output

 Given number : 1134332
 Output : 13432
 Given number : -123300
 Output : -1230
/*
  Swift 4 Program for
  Remove repeated digits in a given number
*/
class Recurring
{
	// Remove recurring digits in a given number
	func removeRecurring(_ x: Int)
	{
		var num: Int = x;
		if (x < 0)
		{
			// When given number is negative
			num = -num;
		}
		// Define some auxiliary variables
		var back: Int = num % 10;
		var current: Int = 0;
		var ans: Int = back;
		var mul: Int = 10;
		num = num / 10;
		while (num > 0)
		{
			current = num % 10;
			if (current  != back)
			{
				// Add current digit at beginning of result
				ans = (current * mul) + ans;
				back = current;
				mul *= 10;
			}
			// reduce number
			num /= 10;
		}
		if (x < 0)
		{
			ans = -ans;
		}
		// Display result
		print("\n Given number : ", x, terminator: "");
		print("\n Output : ", ans, terminator: "");
	}
}
func main()
{
	let task: Recurring = Recurring();
	// Test
	task.removeRecurring(1134332);
	task.removeRecurring(-123300);
}
main();

Output

 Given number :  1134332
 Output :  13432
 Given number :  -123300
 Output :  -1230
/*
  Kotlin Program for
  Remove repeated digits in a given number
*/
class Recurring
{
	// Remove recurring digits in a given number
	fun removeRecurring(x: Int): Unit
	{
		var num: Int = x;
		if (x < 0)
		{
			// When given number is negative
			num = -num;
		}
		// Define some auxiliary variables
		var back: Int = num % 10;
		var current: Int ;
		var ans: Int = back;
		var mul: Int = 10;
		num = num / 10;
		while (num > 0)
		{
			current = num % 10;
			if (current != back)
			{
				// Add current digit at beginning of result
				ans = (current * mul) + ans;
				back = current;
				mul *= 10;
			}
			// reduce number
			num /= 10;
		}
		if (x < 0)
		{
			ans = -ans;
		}
		// Display result
		print("\n Given number : " + x);
		print("\n Output : " + ans);
	}
}
fun main(args: Array < String > ): Unit
{
	var task: Recurring = Recurring();
	// Test
	task.removeRecurring(1134332);
	task.removeRecurring(-123300);
}

Output

 Given number : 1134332
 Output : 13432
 Given number : -123300
 Output : -1230

Time Complexity

Let's analyze the time complexity of the algorithm. The main part of the algorithm involves iterating through the digits of the input number x. The number of digits in x can be represented as O(log10(x)). For each digit, the algorithm performs constant-time operations, so the overall time complexity of the algorithm is O(log10(x)), which can also be approximated as O(log n), where n is the magnitude of the input number.

Resultant Output Explanation

Let's understand the resultant outputs of the example test cases:

Given number: 1134332

Output: 13432

In this example, the input number is 1134332. The algorithm removes the recurring digits 1 and 3, resulting in the output 13432.

Given number: -123300

Output: -1230

Here, the input number is -123300. The algorithm removes the recurring digit 0, and since the number is negative, the output retains the negative sign, resulting in -1230.

Last updated on by Kalkicode




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