不会就坚持67天吧 平方根

class Solution {
    public int mySqrt(int x) {
        int l = 0, r = x, ans = -1;
        while (l <= r) {
            int mid = l + (r - l) / 2;
            if ((long) mid * mid <= x) {
                ans = mid;
                l = mid + 1;
            } else {
                r = mid - 1;
            }
        }
        return ans;
    }
}

作者：LeetCode-Solution
链接：https://leetcode.cn/problems/jJ0w9p/solution/qiu-ping-fang-gen-by-leetcode-solution-ybnw/
来源：力扣（LeetCode）
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。