【Medium】69. Sqrt(x)

Implement int sqrt(int x).

Compute and return the square root of x.

中心思想：

二分查找
sqrt(x) < x/2

class Solution {public:    int mySqrt(int x) { <span style="white-space:pre"></span>double begin = 0;          double end = x;          double result = 1;          double mid = 1;          while(abs(result-x) > 0.000001){              mid = (begin+end)/2;              result = mid*mid;              if(result > x)   // 二分的范围                  end = mid;              else begin = mid;          }          return (int)mid;      }};