开始刷leetcode day10：Sqrt(x)

Implement int sqrt(int x).

Compute and return the square root of x.

Java

public class Solution {
    public int mySqrt(int x) {
        if(x == 0) return 0;
        int start = 1;
        int end = x/2 + 1;
        while(end >= start)
        {
            int s = (start + end)/2;
            if(s <= x/s && (s+1) >x/(s+1) ) return s;
            else if(s < x/s) start = s + 1;
            else  end = s- 1;
        }
        return -1;
    }
}

注意，之前使用s*s <=x && (s+1)*(s+1) > x会导致超时，time limit exceed