Find the celebrity

https://leetcode.com/problems/find-the-celebrity/

// Forward declaration of the knows API.
bool knows(int a, int b);

class Solution {
public:
    int findCelebrity(int n) {

        int left = 0;
        int right = n-1;

        while(left < right)
        {
            if(knows(left, right))
            {
                left++;
            }
            else
            {
                right--;
            }
        }

        for(int i = 0; i<n; i++)
        {
            if(i == left || (knows(i, left) && !knows(left, i)))
            {
                continue;
            }
            else
            {
                return -1;
            }
        }

        return left;


    }

};