题解 | #求平方根#

看到O(logn)就是二分。无脑二分。注意数据范围int最大了

import java.util.*;


public class Solution {
    /**
     * 
     * @param x int整型 
     * @return int整型
     */
    public int sqrt (int x) {
        // write code here
        long left = 1, right = x, mid = (left + right) / 2;
        while(left != mid){
            if(mid * mid == x){
                break;
            }else if(mid * mid > x){
                right = mid;
            }else{
                left = mid;
            }
            mid = (left + right) / 2;
        }
        return (int)mid;
    }
}