38 lines
953 B
C++
38 lines
953 B
C++
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#include <bits/stdc++.h>
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using namespace std;
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//本题目是浮点数二分的板子题
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const double eps = 1e-8;
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double a, B, c, d;
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//方程
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double f(double x) { return a * x * x * x + b * x * x + c * x + d; }
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int main() {
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//输入
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cin >> a >> b >> c >> d;
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double x, y, mid;
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for (int i = -100; i <= 100; i++) {
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x = i, y = i + 1; //左右边界,循环尝试每一个可能的边界，因为题目中说了，每两个解之间的差是不小1的
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//边界
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if (f(x) == 0) {
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printf("%.2f ", x); //如果符合条件则直接输出
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continue;
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}
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//如果其中有解就开始二分
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if (f(x) * f(y) < 0) { //题目中有提示
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//精度要求
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while (y - x >= eps) {
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mid = (x + y) / 2;
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if (f(x) * f(mid) <= 0)
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y = mid; //判断解在哪个区间
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else
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x = mid;
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}
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printf("%.2f ", x);
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}
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}
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return 0;
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}
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