LeetCode每日一题（2020.5.9）

简单二分，注意爆int

class Solution {
    public int mySqrt(int x) {
        int l = 0, r = x;
        while (l < r) {
            int mid = (int)(((long)l + r + 1) >> 1);
            if ((long)mid * mid <= x) l = mid;
            else r = mid - 1;
        }
        return l;
    } 
}