'commit'

LuoGu/RuMen/P1204.cpp

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+#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;
+}