Skip to main content

Find longest substring with repeating characters

Here given code implementation process.

//C Program
//Find longest substring with repeating characters
#include <stdio.h>

//Function which is finding the longest repeating substring
void longest_repeating_char(char * text, int size)
{
	if (size <= 1)
	{
		return;
	}
	//resultatant variables
	int length = -1, counter = 0, location = 0;
	//Loop controlling variable [i,j]
	int i = 0, j = 0;
	//Loop iterating the string elements
	for (i = 0; i < size; ++i)
	{
		//Reset the counter variable
		counter = 0;
		//Loop which is count the length of repeating substring
		for (j = i + 1; j < size; j++)
		{
			if (text[j] == text[i])
			{
				//When same consecutive elements exist
				counter++;
			}
			else
			{
				//When not same consecutive elements exist
				break;
			}
		}
		if (counter > 0 && counter > length)
		{
			//When get a newly longest repeating substring
			location = i;
			length = counter;
		}
		i += counter;
	}
	printf(" Given String : %s\n", text);
	if (length == -1)
	{
		// If no result exists
		printf(" Not found longest repeating substring\n");
		return;
	}
	//When result are exists
	printf(" Longest Repeating Substring : ");
	for (int i = location; i <= location + length; ++i)
	{
		//Display resultant characters
		printf("%c", text[i]);
	}
	printf("\n");
}
int main()
{
	//Define the character elements
	char str[] = "ABFFFFFAABD";
	//Get the size
	int size = sizeof(str) / sizeof(str[0]) - 1;
	//Find result
	longest_repeating_char(str, size);
	//Other test cases
	char str1[] = "ABCCCDCCCCCABBCC";
	size = sizeof(str1) / sizeof(str1[0]) - 1;
	longest_repeating_char(str1, size);
	char str3[] = "AAAAAA";
	size = sizeof(str3) / sizeof(str3[0]) - 1;
	longest_repeating_char(str3, size);
	char str4[] = "ABC";
	size = sizeof(str4) / sizeof(str4[0]) - 1;
	longest_repeating_char(str4, size);
	return 0;
}

Output

 Given String : ABFFFFFAABD
 Longest Repeating Substring : FFFFF
 Given String : ABCCCDCCCCCABBCC
 Longest Repeating Substring : CCCCC
 Given String : AAAAAA
 Longest Repeating Substring : AAAAAA
 Given String : ABC
 Not found longest repeating substring
//Java Program 
//Find longest substring with repeating characters
class MyString
{
	//Function which is finding the longest repeating substring
	public void longest_repeating_char(String text)
	{
       	int size = text.length();
		if (size <= 1)
		{
			return;
		}
		//resultatant variables
		int length = -1, counter = 0, location = 0;
		//Loop controlling variable [i,j]
		int i = 0, j = 0;
		//Loop iterating the string elements
		for (i = 0; i < size; ++i)
		{
			//Reset the counter variable
			counter = 0;
			//Loop which is count the length of repeating substring
			for (j = i + 1; j < size; j++)
			{
				if (text.charAt(j) == text.charAt(i))
				{
					//When same consecutive elements exist
					counter++;
				}
				else
				{
					break;
				}
			}
			if (counter > 0 && counter > length)
			{
				//When get a newly longest repeating substring
				location = i;
				length = counter;
			}
			i += counter;
		}
		System.out.print(" Given String : " + text + "\n");
		if (length == -1)
		{
			// If no result exists
			System.out.print(" Not found longest repeating substring\n");
			return;
		}
		//When result are exists
		System.out.print(" Longest Repeating Substring : ");
		for (i = location; i <= location + length; ++i)
		{
			System.out.print(text.charAt(i));
		}
		System.out.print("\n");
	}
	public static void main(String[] args)
	{
		MyString obj = new MyString();
		obj.longest_repeating_char("ABFFFFFAABD");
		obj.longest_repeating_char("ABCCCDCCCCCABBCC");
		obj.longest_repeating_char("AAAAAA");
		obj.longest_repeating_char("ABC");
	}
}

Output

 Given String : ABFFFFFAABD
 Longest Repeating Substring : FFFFF
 Given String : ABCCCDCCCCCABBCC
 Longest Repeating Substring : CCCCC
 Given String : AAAAAA
 Longest Repeating Substring : AAAAAA
 Given String : ABC
 Not found longest repeating substring
//Include header file
#include <iostream>
#include<string.h>
using namespace std;

//C++ Program 
//Find longest substring with repeating characters
class MyString
{
	public:
		//Function which is finding the longest repeating substring
		void longest_repeating_char(string text)
		{
			int size = text.size();
			if (size <= 1)
			{
				return;
			}
			//resultatant variables
			int length = -1, counter = 0, location = 0;
			//Loop controlling variable [i,j]
			int i = 0, j = 0;
			//Loop iterating the string elements
			for (i = 0; i < size; ++i)
			{
				//Reset the counter variable
				counter = 0;
				//Loop which is count the length of repeating substring
				for (j = i + 1; j < size; j++)
				{
					if (text[j] == text[i])
					{
						//When same consecutive elements exist
						counter++;
					}
					else
					{
						break;
					}
				}
				if (counter > 0 && counter > length)
				{
					//When get a newly longest repeating substring
					location = i;
					length = counter;
				}
				i += counter;
			}
			cout << " Given String : " << text << "\n";
			if (length == -1)
			{
				// If no result exists
				cout << " Not found longest repeating substring\n";
				return;
			}
			//When result are exists
			cout << " Longest Repeating Substring : ";
			for (i = location; i <= location + length; ++i)
			{
				cout << text[i];
			}
			cout << "\n";
		}
};
int main()
{
	MyString obj = MyString();
	obj.longest_repeating_char("ABFFFFFAABD");
	obj.longest_repeating_char("ABCCCDCCCCCABBCC");
	obj.longest_repeating_char("AAAAAA");
	obj.longest_repeating_char("ABC");
	return 0;
}

Output

 Given String : ABFFFFFAABD
 Longest Repeating Substring : FFFFF
 Given String : ABCCCDCCCCCABBCC
 Longest Repeating Substring : CCCCC
 Given String : AAAAAA
 Longest Repeating Substring : AAAAAA
 Given String : ABC
 Not found longest repeating substring
//Include namespace system
using System;

//C# Program 
//Find longest substring with repeating characters
class MyString
{
	//Function which is finding the longest repeating substring
	public void longest_repeating_char(String text)
	{
		int size = text.Length;
		if (size <= 1)
		{
			return;
		}
		//resultatant variables
		int length = -1, counter = 0, location = 0;
		//Loop controlling variable [i,j]
		int i = 0, j = 0;
		//Loop iterating the string elements
		for (i = 0; i < size; ++i)
		{
			//Reset the counter variable
			counter = 0;
			//Loop which is count the length of repeating substring
			for (j = i + 1; j < size; j++)
			{
				if (text[j] == text[i])
				{
					//When same consecutive elements exist
					counter++;
				}
				else
				{
					break;
				}
			}
			if (counter > 0 && counter > length)
			{
				//When get a newly longest repeating substring
				location = i;
				length = counter;
			}
			i += counter;
		}
		Console.Write(" Given String : " + text + "\n");
		if (length == -1)
		{
			// If no result exists
			Console.Write(" Not found longest repeating substring\n");
			return;
		}
		//When result are exists
		Console.Write(" Longest Repeating Substring : ");
		for (i = location; i <= location + length; ++i)
		{
			Console.Write(text[i]);
		}
		Console.Write("\n");
	}
	public static void Main(String[] args)
	{
		MyString obj = new MyString();
		obj.longest_repeating_char("ABFFFFFAABD");
		obj.longest_repeating_char("ABCCCDCCCCCABBCC");
		obj.longest_repeating_char("AAAAAA");
		obj.longest_repeating_char("ABC");
	}
}

Output

 Given String : ABFFFFFAABD
 Longest Repeating Substring : FFFFF
 Given String : ABCCCDCCCCCABBCC
 Longest Repeating Substring : CCCCC
 Given String : AAAAAA
 Longest Repeating Substring : AAAAAA
 Given String : ABC
 Not found longest repeating substring
<?php
//Php Program 
//Find longest substring with repeating characters
class MyString
{
	//Function which is finding the longest repeating substring
	public	function longest_repeating_char($text)
	{
		$size = strlen($text);
		if ($size <= 1)
		{
			return;
		}
		//resultatant variables
		$length = -1;
		$counter = 0;
		$location = 0;
		//Loop controlling variable [i,j]
		$i = 0;
		$j = 0;
		//Loop iterating the string elements
		for ($i = 0; $i < $size; ++$i)
		{
			//Reset the counter variable
			$counter = 0;
			//Loop which is count the length of repeating substring
			for ($j = $i + 1; $j < $size; $j++)
			{
				if ($text[$j] == $text[$i])
				{
					//When same consecutive elements exist
					$counter++;
				}
				else
				{
					break;
				}
			}
			if ($counter > 0 && $counter > $length)
			{
				//When get a newly longest repeating substring
				$location = $i;
				$length = $counter;
			}
			$i += $counter;
		}
		echo " Given String : ". $text ."\n";
		if ($length == -1)
		{
			echo " Not found longest repeating substring\n";
			return;
		}
		echo " Longest Repeating Substring : ";
		for ($i = $location; $i <= $location + $length; ++$i)
		{
			echo $text[$i];
		}
		echo "\n";
	}
}

function main()
{
	$obj = new MyString();
	$obj->longest_repeating_char("ABFFFFFAABD");
	$obj->longest_repeating_char("ABCCCDCCCCCABBCC");
	$obj->longest_repeating_char("AAAAAA");
	$obj->longest_repeating_char("ABC");
}
main();

Output

 Given String : ABFFFFFAABD
 Longest Repeating Substring : FFFFF
 Given String : ABCCCDCCCCCABBCC
 Longest Repeating Substring : CCCCC
 Given String : AAAAAA
 Longest Repeating Substring : AAAAAA
 Given String : ABC
 Not found longest repeating substring
//Node Js Program 
//Find longest substring with repeating characters
class MyString
{
	//Function which is finding the longest repeating substring
	longest_repeating_char(text)
	{
		var size = text.length;
		if (size <= 1)
		{
			return;
		}
		//resultatant variables
		var length = -1;
		var counter = 0;
		var location = 0;
		//Loop controlling variable [i,j]
		var i = 0;
		var j = 0;
		//Loop iterating the string elements
		for (i = 0; i < size; ++i)
		{
			//Reset the counter variable
			counter = 0;
			//Loop which is count the length of repeating substring
			for (j = i + 1; j < size; j++)
			{
				if (text[j] == text[i])
				{
					//When same consecutive elements exist
					counter++;
				}
				else
				{
					break;
				}
			}
			if (counter > 0 && counter > length)
			{
				//When get a newly longest repeating substring
				location = i;
				length = counter;
			}
			i += counter;
		}
		process.stdout.write(" Given String : " + text + "\n");
		if (length == -1)
		{
			process.stdout.write(" Not found longest repeating substring\n");
			return;
		}
		process.stdout.write(" Longest Repeating Substring : ");
		for (i = location; i <= location + length; ++i)
		{
			process.stdout.write(text[i]);
		}
		process.stdout.write("\n");
	}
}

function main()
{
	var obj = new MyString();
	obj.longest_repeating_char("ABFFFFFAABD");
	obj.longest_repeating_char("ABCCCDCCCCCABBCC");
	obj.longest_repeating_char("AAAAAA");
	obj.longest_repeating_char("ABC");
}
main();

Output

 Given String : ABFFFFFAABD
 Longest Repeating Substring : FFFFF
 Given String : ABCCCDCCCCCABBCC
 Longest Repeating Substring : CCCCC
 Given String : AAAAAA
 Longest Repeating Substring : AAAAAA
 Given String : ABC
 Not found longest repeating substring
# Python 3 Program 
# Find longest substring with repeating characters
class MyString :
	# Function which is finding the longest repeating substring
	def longest_repeating_char(self, text) :
		size = len(text)
		if (size <= 1) :
			return
		
		# resultatant variables
		length = -1
		counter = 0
		location = 0
		# Loop controlling variable [i,j]
		i = 0
		j = 0
		# Loop iterating the string elements
		while (i < size) :
			# Reset the counter variable
			counter = 0
			j = i + 1
			# Loop which is count the length of repeating substring
			while (j < size) :
				if (text[j] == text[i]) :
					# When same consecutive elements exist
					counter += 1
				else :
					break
				
				j += 1
			
			if (counter > 0 and counter > length) :
				# When get a newly longest repeating substring
				location = i
				length = counter
			
			i += counter
			i += 1
		
		print(" Given String : ", text ,"\n", end = "")
		if (length == -1) :
			print(" Not found longest repeating substring\n", end = "")
			return
		
		print(" Longest Repeating Substring : ", end = "")
		i = location
		while (i <= location + length) :
			print(text[i], end = "")
			i += 1
		
		print("\n", end = "")
	

def main() :
	obj = MyString()
	obj.longest_repeating_char("ABFFFFFAABD")
	obj.longest_repeating_char("ABCCCDCCCCCABBCC")
	obj.longest_repeating_char("AAAAAA")
	obj.longest_repeating_char("ABC")

if __name__ == "__main__": main()

Output

 Given String :  ABFFFFFAABD
 Longest Repeating Substring : FFFFF
 Given String :  ABCCCDCCCCCABBCC
 Longest Repeating Substring : CCCCC
 Given String :  AAAAAA
 Longest Repeating Substring : AAAAAA
 Given String :  ABC
 Not found longest repeating substring
# Ruby Program 
# Find longest substring with repeating characters
class MyString

	# Function which is finding the longest repeating substring
	def longest_repeating_char(text)
	
		size = text.length()
		if (size <= 1)
		
			return
		end
		# resultatant variables
		length = -1
		counter = 0
		location = 0
		# Loop controlling variable [i,j]
		i = 0
		j = 0
		# Loop iterating the string elements
		while (i < size)
		
			# Reset the counter variable
			counter = 0
			j = i + 1
			# Loop which is count the length of repeating substring
			while (j < size)
			
				if (text[j] == text[i])
				
					# When same consecutive elements exist
					counter += 1
				else
				
					break
				end
				j += 1
			end
			if (counter > 0 && counter > length)
			
				# When get a newly longest repeating substring
				location = i
				length = counter
			end
			i += counter
			i += 1
		end
		print(" Given String : ", text ,"\n")
		if (length == -1)
		
			#  If no result exists
			print(" Not found longest repeating substring\n")
			return
		end
		# When result are exists
		print(" Longest Repeating Substring : ")
		i = location
		while (i <= location + length)
		
			print(text[i])
			i += 1
		end
		print("\n")
	end
end
def main()

	obj = MyString.new()
	obj.longest_repeating_char("ABFFFFFAABD")
	obj.longest_repeating_char("ABCCCDCCCCCABBCC")
	obj.longest_repeating_char("AAAAAA")
	obj.longest_repeating_char("ABC")
end
main()

Output

 Given String : ABFFFFFAABD
 Longest Repeating Substring : FFFFF
 Given String : ABCCCDCCCCCABBCC
 Longest Repeating Substring : CCCCC
 Given String : AAAAAA
 Longest Repeating Substring : AAAAAA
 Given String : ABC
 Not found longest repeating substring

import scala.util.control.Breaks._
//Scala Program 
//Find longest substring with repeating characters
class MyString
{
	//Function which is finding the longest repeating substring
	def longest_repeating_char(text: String): Unit = {
		var size: Int = text.length();
		if (size <= 1)
		{
			return;
		}
		//resultatant variables
		var length: Int = -1;
		var counter: Int = 0;
		var location: Int = 0;
		//Loop controlling variable [i,j]
		var i: Int = 0;
		var j: Int = 0;
		//Loop iterating the string elements
		while (i < size)
		{
			//Reset the counter variable
			counter = 0;
			j = i + 1;
            breakable {
			//Loop which is count the length of repeating substring
			while (j < size)
			{
				if (text(j) == text(i))
				{
					//When same consecutive elements exist
					counter += 1;
				}
				else
				{
					break;
				}
				j += 1;
			}
            }
			if (counter > 0 && counter > length)
			{
				//When get a newly longest repeating substring
				location = i;
				length = counter;
			}
			i += counter;
			i += 1;
		}
		print(" Given String : " + text + "\n");
		if (length == -1)
		{
			// If no result exists
			print(" Not found longest repeating substring\n");
			return;
		}
		//When result are exists
		print(" Longest Repeating Substring : ");
		i = location;
		while (i <= location + length)
		{
			print(text(i));
			i += 1;
		}
		print("\n");
	}
}
object Main
{
	def main(args: Array[String]): Unit = {
		var obj: MyString = new MyString();
		obj.longest_repeating_char("ABFFFFFAABD");
		obj.longest_repeating_char("ABCCCDCCCCCABBCC");
		obj.longest_repeating_char("AAAAAA");
		obj.longest_repeating_char("ABC");
	}
}

Output

 Given String : ABFFFFFAABD
 Longest Repeating Substring : FFFFF
 Given String : ABCCCDCCCCCABBCC
 Longest Repeating Substring : CCCCC
 Given String : AAAAAA
 Longest Repeating Substring : AAAAAA
 Given String : ABC
 Not found longest repeating substring
//Swift Program 
//Find longest substring with repeating characters
class MyString
{
	//Function which is finding the longest repeating substring
	func longest_repeating_char(_ text: String)
	{
		let size: Int = text.count;
      	let arr = Array(text);
		if (size <= 1)
		{
			return;
		}
		//resultatant variables
		var length: Int = -1;
		var counter: Int = 0;
		var location: Int = 0;
		//Loop controlling variable [i,j]
		var i: Int = 0;
		var j: Int = 0;
		//Loop iterating the string elements
		while (i < size)
		{
			//Reset the counter variable
			counter = 0;
			j = i + 1;
			//Loop which is count the length of repeating substring
			while (j < size)
			{
				if (arr[j] == arr[i])
				{
					//When same consecutive elements exist
					counter += 1;
				}
				else
				{
					break;
				}
				j += 1;
			}
			if (counter > 0 && counter > length)
			{
				//When get a newly longest repeating substring
				location = i;
				length = counter;
			}
			i += counter;
			i += 1;
		}
		print(" Given String : ", text ,"\n", terminator: "");
		if (length == -1)
		{
			print(" Not found longest repeating substring\n", terminator: "");
			return;
		}
		print(" Longest Repeating Substring : ", terminator: "");
		i = location;
		while (i <= location + length)
		{
			print(arr[i], terminator: "");
			i += 1;
		}
		print("\n", terminator: "");
	}
}
func main()
{
	let obj: MyString = MyString();
	obj.longest_repeating_char("ABFFFFFAABD");
	obj.longest_repeating_char("ABCCCDCCCCCABBCC");
	obj.longest_repeating_char("AAAAAA");
	obj.longest_repeating_char("ABC");
}
main();

Output

 Given String :  ABFFFFFAABD
 Longest Repeating Substring : FFFFF
 Given String :  ABCCCDCCCCCABBCC
 Longest Repeating Substring : CCCCC
 Given String :  AAAAAA
 Longest Repeating Substring : AAAAAA
 Given String :  ABC
 Not found longest repeating substring
Last updated on by Kalkicode




Comment

Please share your knowledge to improve code and content standard. Also submit your doubts, and test case. We improve by your feedback. We will try to resolve your query as soon as possible.

New Comment