Leetcode 69. Sqrt(x)

1 class Solution {
2 public:
3     int mySqrt(int x) {//1579205274
4         int half=(int)sqrt(x);
5         return half;
6     }
7 };

 1 class Solution {
 2 public:
 3     int mySqrt(int x) {//1579205274
 4         if(x<=1){
 5             return x;
 6         }
 7         int left=1,right=x,mid;//左闭右开
 8         while(left<right){
 9             mid=left+(right-left)/2;//直接使用(high + low) / 2 可能导致溢出
10             if(x/mid>=mid){
11                 left=mid+1;
12             }
13             else{
14                 right=mid;
15             }
16         }
17         return left-1;
18     }
19 };