Method helper

Recursion/Homework/palindrome.cpp:11–19

class Solution{
public:	
	int helper(string S, int start, int end){
	    if (start>=end){
	        return 1;
	    }
	    if(S[start]!=S[end]){
	        return 0;
	    }
	    return helper(S, start+1, end-1);
	}
	
	int isPalindrome(string S)
	{