633. Sum of Square Numbers

Given a non-negative integer c, your task is to decide whether there’re two integers a and b such that a2 + b2 = c.

Example 1:

Input: 5
Output: True
Explanation: 1 * 1 + 2 * 2 = 5

Example 2:

Input: 3
Output: False

bool judgeSquareSum(int c) {
if (c == 0)return true;
int high = sqrt(c);
for (int low = 0, p = high; low <= high && p >= 0;){
int sum = pow(low, 2) + pow(p, 2);
if (sum < c)low++;
else if (sum > c)p--;
else return true;
}
return false;
}