From 338fd50ccadcbcc3a6ce7441b77da7623d5d78cb Mon Sep 17 00:00:00 2001
From: Ren Baoshuo <i@baoshuo.ren>
Date: Sun, 20 Dec 2020 09:07:48 +0800
Subject: [PATCH] =?UTF-8?q?P3382=20=E3=80=90=E6=A8=A1=E6=9D=BF=E3=80=91?=
 =?UTF-8?q?=E4=B8=89=E5=88=86=E6=B3=95?=
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R43941020
---
 problem/P3382/P3382.cpp | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 problem/P3382/P3382.cpp

diff --git a/problem/P3382/P3382.cpp b/problem/P3382/P3382.cpp
new file mode 100644
index 00000000..f8821546
--- /dev/null
+++ b/problem/P3382/P3382.cpp
@@ -0,0 +1,34 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+const double eps = 1e-11;
+int n;
+double l, r, a[20], mid1, mid2;
+
+double f(double x) {
+    double s = 0;
+    for (int i = n; i >= 0; i--) {
+        s = s * x + a[i];
+    }
+    return s;
+}
+
+int main() {
+    cin >> n >> l >> r;
+    for (int i = n; i >= 0; i--) {
+        cin >> a[i];
+    }
+    while (r - l >= eps) {
+        mid1 = l + (r - l) / 3.0;
+        mid2 = r - (r - l) / 3.0;
+        if (f(mid1) > f(mid2)) {
+            r = mid2;
+        }
+        else {
+            l = mid1;
+        }
+    }
+    cout << fixed << setprecision(5) << l << endl;
+    return 0;
+}