LeetCode 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

题目大意：给一个数c，判断是否存在两个数字a
b满足a*a+b*b=c，存在就返回true，否则返回false

分析：i和j分别从根号c开始到0，如果找到了i
* i + j * j == c就return true，如果i * i + j * j < c就break第二层for循环，最后如果都没有找到就返回false～

class Solution {
public:
bool judgeSquareSum(int c) {
int t = sqrt(c);
for (int i = t; i >= 0; i--) {
for (int j = t; j >= 0; j--) {
if (i * i + j * j == c) return true;
if (i * i + j * j < c) break;
}
}
return false;
}
};