Valid Palindrome Error

[Vijay0753]

Given a non-empty string s, you may delete at most one character. Judge whether you can make it a palindrome.

Example 1:
Input: "aba"
Output: True
Example 2:
Input: "abca"
Output: True
Explanation: You could delete the character 'c'.
Note:
The string will only contain lowercase characters a-z. The maximum length of the string is 50000

  class Solution {
public:
      bool validPalindrome(string s)
                {
                    int left = 0;
                    int right = s.length()-1;

                    while(left<=right)
                    {
                        if(s[left]==s[right])
                        {
                            left++;
                            right--;
                        }
                        else
                        {
                            return (isPalindrome(left+1,right,s)||isPalindrome(left,right-1,s));
                        }  
                    }
                    return true;
                }
    
    
    
    bool isPalindrome(int a, int b, string str)
                {
                    while(a<=b)
                    {
                     if(str[a]!=str[b])
                    {
                        return false;
                    }
                        a++;
                        b--;
                    }
                     return true;
                }
    
    
};

Error: Line 506: Char 9: runtime error: pointer index expression with base 0x000000000000 overflowed to 0xffffffffffffffff (basic_string.h)


What am I missing here?

[dutch]

What am I missing here?

You're missing a complete program that we can run with the push of a button.
And you're missing the input that caused the problem.

BTW, C++ is not Java!
Don't stick your functions in a class for no reason.
If you want a namespace, use a namespace.

[dutch]

This seems to be equivalent to what you wrote, and I don't get any errors.

#include <iostream>
#include <string>
using namespace std;

bool isPalindrome(string s, int left, int right)
{
    while (left < right)
        if (s[left++] != s[right--])
            return false;
    return true;
}

bool nearPalindrome(string s)
{
    int left = 0, right = s.length() - 1;
    while (left < right)
        if (s[left++] != s[right--])
            return isPalindrome(s, left,   right+1)
                || isPalindrome(s, left-1, right  );
    return true;
}

int main()
{
    cout << nearPalindrome("") << '\n';
    cout << nearPalindrome("aba") << '\n';
    cout << nearPalindrome("abca") << '\n';
    cout << nearPalindrome("abcdedcxba") << '\n';
    cout << nearPalindrome("abcdyedcxba") << '\n';
}

Here's your original code (with the spacing fixed):

#include <iostream>
#include <string>
using namespace std;

class Solution {
public:
    bool validPalindrome(string s)
    {
        int left = 0;
        int right = s.length()-1;

        while (left <= right)
        {
            if (s[left] == s[right])
            {
                left++;
                right--;
            }
            else
            {
                return isPalindrome(left+1, right,   s)
                    || isPalindrome(left,   right-1, s);
            }  
        }
        return true;
    }

    bool isPalindrome(int a, int b, string str)
    {
        while (a <= b)
        {
            if (str[a] != str[b])
            {
                return false;
            }
            a++;
            b--;
        }
        return true;
    }
};

int main()
{
    Solution s;
    cout << s.validPalindrome("") << '\n';
    cout << s.validPalindrome("aba") << '\n';
    cout << s.validPalindrome("abca") << '\n';
    cout << s.validPalindrome("abcdedcxba") << '\n';
    cout << s.validPalindrome("abcdyedcxba") << '\n';
}