[LeetCode]69. Sqrt(x)

[LeetCode]69. Sqrt(x)

题目描述

思路

由于题目要求返回的是整数，简单实现的话可以使用二分
注意实现过程中的一些越界问题

代码

#include <iostream>

using namespace std;

class Solution {
public:
    int mySqrt(int x) {
        if (x == 1)
            return 1;
        int start = 0, end = x;
        while (start < end) {
            //越界点1 end + start 会越界
            int mid = ((end - start) >> 1) + start;
            //越界点2 mid * mid 会越界
            if (mid == x / mid) return mid;
            else if (start == mid || end == mid) return start;
            else if (mid < x / mid) start = mid;
            else end = mid;
        }
        return end;
    }
};

int main() {
    Solution s;
    cout << s.mySqrt(2147395599) << endl;
    system("pause");
    return 0;
}