leetcode 69. Sqrt(x)

最新推荐文章于 2024-10-22 10:05:07 发布

转载最新推荐文章于 2024-10-22 10:05:07 发布 · 57 阅读

本文介绍两种求解整数平方根的方法：牛顿迭代法和二分查找法。牛顿迭代法通过迭代逼近求解，而二分查找法则利用了数值的有序特性进行快速定位。

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牛顿迭代法

https://blog.youkuaiyun.com/hnu2012/article/details/72598038

https://www.cnblogs.com/liujinhong/p/6014973.html

//牛顿法

class Solution {
public:
    int mySqrt(int x) {
        if (x <= 1) 
            return x; 
        double x1 = 0, x2 = 1; 
        while (abs(x1 - x2) > 0.000001) { 
            x1 = x2; 
            x2 = x1 / 2 + (double)x / (2 * x1); 
        }
        return (int)x1;

    }
};

//二分查找法

class Solution {
public:
    int mySqrt(int x) {
        if (x <= 1) return x;
        int left = 0, right = x;
        while (left < right) {
            int mid = left + (right - left) / 2;
            if (x / mid >= mid) left = mid + 1;
            else right = mid;
        }
        return right - 1;
    }
};