Program to find the longest repeating sequence in a string

Python

#Checks for the largest common prefix  
def lcp(s, t):  
  n = min(len(s),len(t));  
  for i in range(0,n):  
    if(s[i] != t[i]):  
      return s[0:i];  
  else:  
    return s[0:n];  
   
str = "acbdfghybdf";  
lrs="";  
n = len(str);  
for i in range(0,n):  
  for j in range(i+1,n):  
    #Checks for the largest common factors in every substring  
    x = lcp(str[i:n],str[j:n]);  
        #If the current prefix is greater than previous one   
        #then it takes the current one as longest repeating sequence  
    if(len(x) > len(lrs)):  
      lrs=x;    
print("Longest repeating sequence: "+lrs);  

Output:

Longest repeating sequence: bdf

C

#include <stdio.h>  
#include <string.h>  
#define MIN(x, y) (((x) < (y)) ? (x) : (y))  
//User-defined substring function that will take string(str), position(p) and no of character(len) as input  
//Produces result c as output  
void substring(char s[], char sub[], int p, int len){  
 int c = 0;  
 while (c < len) {  
 sub[c] = s[p+c];  
  c++;  
}  
 sub[c] = '\0';  
}  
  
//Function thats gives the longest common prefix among two strings.  
int lcp(char s[], char t[],char a[]){  
 int n = MIN(strlen(s),strlen(t));  
for(int i = 0; i < n; i++){  
  if(s[i] != t[i]){  
   substring(s,a,0,i);  
    return 0;  
 }  
}  
substring(s,a,0,n);  
return 0;  
}  
  
int main()  
{  
  char str[] = "acbdfghybdf";  
char lrs[30], x[30], res[30], sub[30],sub1[30];  
int i,j,n = strlen(str);  
for(i = 0; i < n; i++){  
 for(j = i+1; j < n; j++){  
    //For comparing each substring with every other substring  
   substring(str,sub,i,n);  
        substring(str,sub1,j,n);  
   cp(sub,sub1,x);  
    //lrs keeps track of the longest repeating sequence  
    if(strlen(x) > strlen(lrs)) strncpy(lrs, x, strlen(x));  
 }  
}  
printf("Longest repeating sequence: %s",lrs);  
  return 0;  
}  

Output:

Longest repeating sequence: bdf

JAVA

public class LongestRepeatingSequence {  
    //Checks for the largest common prefix  
    public static String lcp(String s, String t){  
        int n = Math.min(s.length(),t.length());  
        for(int i = 0; i < n; i++){  
            if(s.charAt(i) != t.charAt(i)){  
                return s.substring(0,i);  
            }  
        }  
        return s.substring(0,n);  
    }  
      
    public static void main(String[] args) {  
        String str = "acbdfghybdf";  
        String lrs="";  
        int n = str.length();  
        for(int i = 0; i < n; i++){  
            for(int j = i+1; j < n; j++){  
                //Checks for the largest common factors in every substring  
                String x = lcp(str.substring(i,n),str.substring(j,n));  
                //If the current prefix is greater than previous one   
                //then it takes the current one as longest repeating sequence  
                if(x.length() > lrs.length()) lrs=x;    
            }  
        }  
        System.out.println("Longest repeating sequence: "+lrs);  
    }  
}  

Output:

Longest repeating sequence: bdf

C#

using System;                   
public class Program  
{  
    //Checks for the largest common prefix  
    public static String lcp(String s, String t){  
        int n = Math.Min(s.Length,t.Length);  
        for(int i = 0; i < n; i++){  
            if(s[i] != t[i]){  
                return s.Substring(0,i);  
            }  
        }  
        return s.Substring(0,n);  
    }  
      
    public static void Main()  
    {  
        String str = "acbdfghybdf";  
        String lrs="";  
        int n = str.Length;  
        for(int i = 0; i < n; i++){  
           for(int j = i+1; j < n-i; j++){  
                //Checks for the largest common factors in every substring  
                String x = lcp(str.Substring(i),str.Substring(j));  
                //If the current prefix is greater than previous one   
                //then it takes the current one as longest repeating sequence  
               if(x.Length > lrs.Length) lrs=x;    
            }  
        }  
       Console.WriteLine("Longest repeating sequence: "+lrs);  
    }  
}  

Output:

Longest repeating sequence: bdf

PHP

<!DOCTYPE html>   
<html>   
<body>   
<?php   
//Checks for the largest common prefix  
function lcp($s, $t){  
    $n = min(strlen($s),strlen($t));  
    for($i = 0; $i < $n; $i++){  
        if($s[$i] != $t[$i]){  
            return substr($s,0,$i);  
        }  
    }  
    return substr($s,0,$n);  
}  
      
$str = "acbdfghybdf";  
$lrs="";  
$n = strlen($str);  
for($i = 0; $i < $n; $i++){  
    for($j = ($i+1); $j < ($n-$i); $j++){  
        //Checks for the largest common factors in every substring  
        $x = lcp(substr($str,$i),substr($str,$j));  
        //If the current prefix is greater than previous one   
        //then it takes the current one as largest repeating sequence  
        if(strlen($x) > strlen($lrs))  
        {   
            $lrs=$x;  
        }    
    }  
}  
echo "Longest repeating sequence: $lrs";  
?>   
</body>   
</html>  

Output:

Longest repeating sequence: bdf