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
思路：
类似于二分查找。
从0 和sqrt(n)两端分别查找。
bool judgeSquareSum(int c) { if(c==0)return true; int qq = sqrt( (double)c ); for( int ii= 0, pp = qq; ii<= qq && pp >= ii; ) { int sum = ii * ii + pp * pp; if( sum < c ) ii++; else if( sum > c ) pp--; else return true; } return false; }
[leetcode-633-Sum of Square Numbers]
原文：http://www.cnblogs.com/hellowooorld/p/7105637.html