python/LuoGu/RuMen/P1204.cpp

#include <bits/stdc++.h>
//P1204
using namespace std;
double a, b, c, d;

double f(double x) {
    return a * x * x * x + b * x * x + c * x + d;//方程部分
}

int main() {
    int i;
    double x, y, mid;
    cin >> a >> b >> c >> d;
    for (i = -100; i <= 100; i++)//循环，枚举查找
    {
        x = i;
        y = x + 1;//两个指针
        if (f(x) == 0) {
            printf("%.2f", x);
            cout << " ";
        }//如果符合条件则直接输出
        else if (f(x) * f(y) < 0)//如果其中有解就开始二分
        {
            while (y - x >= 0.001)//精度要求
            {
                mid = (x + y) / 2;
                if (f(mid) * f(x) <= 0)y = mid;//判断解在哪个区间
                else x = mid;
            }
            printf("%.2f", x);
            cout << " ";
        }
    }
    return 0;
}