LeetCode 069 Sqrt(x) 求平方根

Implement int sqrt(int x).
Compute and return the square root of x.
x is guaranteed to be a non-negative integer.
Example 1:
Input: 4
Output: 2
Example 2:
Input: 8
Output: 2
Explanation: The square root of 8 is 2.82842..., and since we want to return an integer, the decimal part will be truncated.
（1）暴力搜索

 class Solution {
 public:
     int mySqrt(int x) {
         if(x<=)
             return x;
         int begin=;
         int end=x;
         int mid=;
         while(begin<=end)
         {
             mid=(begin+end)/;
             if(mid==x/mid)
                 return mid;
             else if(mid<x/mid)
                 begin=mid+;
             else
                 end=mid-;
         }
         return end;
     }
 };

（2）牛顿迭代

 class Solution {
 public:
     int mySqrt(int x)
     {
         long long v=x;
         while(v*v>x)
             v=(v+x/v)>>;
         return v;
     }
 };