LeetCode 633. 平方数之和(双指针法)

class Solution
{
public:
    bool judgeSquareSum(int c)
    {
        long left = 0, right = sqrt(c);
        while (left <= right)
        {
            long tmp = left * left + right * right;
            if (tmp == c)
            {
                return true;
            }
            else if (tmp > c)
            {
                right--;
            }
            else
            {
                left++;
            }
        }
        return false;
    }
};