Valid Perfect Square

class Solution {
public:
    bool isPerfectSquare(int num) {
        int left = 0;
        int right = num;
        while(left <= right) {
            long mid = (left + right) / 2;
            long square = mid * mid;
            if(square == num) {
                return true;
            }
            if(square > num) {
                right = mid - 1;
            }
            else {
                left = mid + 1;
            }
        }
        return false;
    }
};