Sum of Square Numbers问题描述

问题描述：

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

示例：

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

Input: 3
Output: False

问题分析：

分析可知，a和b的取值范围在[0,√c]之间，于是乎我们可以遍历寻找a和b。

过程详见代码：

class Solution {
public:
    bool judgeSquareSum(int c) {
        int high = sqrt(c);
		int low = 0;
		while (low < high)
		{
			int sum = low * low + high * high;
			if (sum == c) return true;
			else if (sum < c) low++;
			else high--;
		}
		if (low * low + high * high == c) return true;
		return false;
    }
};