LeetCode-Sqrt(x)

题目：https://oj.leetcode.com/problems/sqrtx/

Implement int sqrt(int x).

Compute and return the square root of x.

分析：二分查找

源码：Java版本
算法分析：时间复杂度O(logn)，空间复杂度O(1)

public class Solution {
    public int sqrt(int x) {
        if(x<=1) {
            return x;
        }
        int left=1,closeLeft=0,middle,right=x/2;
        while(left<=right) {
            middle=left+(right-left)/2;
            if(x/middle>middle) {
                left=middle+1;
                closeLeft=middle;
            }else if(x/middle<middle) {
                right=middle-1;
            }else {
                return middle;
            }
        }
        return closeLeft;
    }
}