LeetCode Sqrt(x)

Description:

Compute and return the square root of x.

Solution:

二分咯，但是对于l<r的判断，需要对x=0和1的情况进行特判。

import java.util.*;

public class Solution {
	public int mySqrt(int x) {
		if (x == 0 || x == 1)
			return x;
		long l = 0, r = x, mid;

		while (l < r) {
			mid = (l + r) / 2;
			if (mid * mid <= x && (mid + 1) * (mid + 1) > x) {
				return (int) mid;
			}
			if (mid * mid > x)
				r = mid;
			else
				l = mid;
		}
		return (int) l;
	}
}