Longest Even Length Substring Solution in O(1) space

Longest Even Length Substring Solution in O(1) space

  June 16, 2017    

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Problem: Find a longest substring which has sum of left elements from mid is equal to right element 

Sol : Iterate over the string and  check for midpoint (every) and create leftsum and rightsum variables to hold respective sum and check whether they are equal and if they are greater than maximum substring having same property

code :

import java.util.*;
import java.lang.*;
import java.io.*;
class GFG
 {
     public static int length(String str)
     {
         int len=str.length();
         int length=0;
         for(int i=0;i<=len-2;i++)
         {
             int left=i;
             int right=i+1;
             int leftsum,rightsum;
             leftsum=rightsum=0;
             while(right<len && left>=0)
             {
                 leftsum+=str.charAt(left)-'0';
                 rightsum+=str.charAt(right)-'0';
                 if(leftsum==rightsum)
                 length=Math.max(length,right-left+1);
                 left--;
                 right++;
                 
             }
         }
         return length;
     }
public static void main (String[] args)
{
Scanner ab=new Scanner(System.in);
int t=ab.nextInt();
while(t-->0)
{
   String str=ab.next();
   System.out.println(length(str));
}
}
}