Sum of Square Numbers — C++

// Time:  O(sqrt(c) * logc)
// Space: O(1)

class Solution {
public:
    bool judgeSquareSum(int c) {
        for (long long a = 0; a * a <= c; ++a) {
            auto b = static_cast<int>(sqrt(c - a * a));
            if (a * a + b * b == c) {
                return true;
            }
        }
        return false;
    }
};