基础算法：浮点数二分

题目描述

代码参考

#include <iostream>

using namespace std;

double x;

int main()
{
    cin >> x;
    
    double l = -10000, r = 10000;
    while (r - l > 1e-8)
    {
        double mid = (r - l) / 2;
        if (mid * mid * mid >= x) r = mid;
        else l = mid;
    }
    
    printf("%lf\n", l);
    
    return 0;
}

浮点数二分算法模板

bool check(double x) {/* ... */} // 检查x是否满足某种性质

double bsearch_3(double l, double r)
{
    const double eps = 1e-6;   // eps 表示精度，取决于题目对精度的要求
    while (r - l > eps)
    {
        double mid = (l + r) / 2;
        if (check(mid)) r = mid;
        else l = mid;
    }
    return l;
}