From ce02e8de140eab61b96b094e257eb35659d3c502 Mon Sep 17 00:00:00 2001
From: Baoshuo <i@baoshuo.ren>
Date: Sat, 11 Jun 2022 18:35:30 +0800
Subject: [PATCH] =?UTF-8?q?P3177=20[HAOI2015]=20=E6=A0=91=E4=B8=8A?=
 =?UTF-8?q?=E6=9F=93=E8=89=B2?=
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https://www.luogu.com.cn/record/77254489
---
 Luogu/P3177/P3177.cpp | 65 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 Luogu/P3177/P3177.cpp

diff --git a/Luogu/P3177/P3177.cpp b/Luogu/P3177/P3177.cpp
new file mode 100644
index 00000000..f20dc83a
--- /dev/null
+++ b/Luogu/P3177/P3177.cpp
@@ -0,0 +1,65 @@
+#include <iostream>
+#include <cstring>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2005;
+
+int n, k, fa[N], siz[N];
+long long f[N][N];
+std::vector<std::pair<int, int>> g[N];
+
+void dfs(int u, int fa) {
+    siz[u] = 1;
+    f[u][0] = f[u][1] = 0;
+
+    for (auto e : g[u]) {
+        int v = e.first,
+            w = e.second;
+
+        if (v == fa) continue;
+
+        dfs(v, u);
+
+        siz[u] += siz[v];
+
+        for (int i = std::min(k, siz[u]); ~i; i--) {
+            if (~f[u][i]) {
+                f[u][i] += f[v][0] + 1ll * siz[v] * (n - k - siz[v]) * w;
+            }
+
+            for (int j = std::min(i, siz[v]); j; j--) {
+                if (~f[u][i - j]) {
+                    f[u][i] = std::max(f[u][i], f[u][i - j] + f[v][j] + 1ll * (j * (k - j) + (siz[v] - j) * (n - k - siz[v] + j)) * w);
+                }
+            }
+        }
+    }
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> k;
+
+    k = std::max(k, n - k);
+
+    for (int i = 1, u, v, w; i < n; i++) {
+        cin >> u >> v >> w;
+
+        g[u].push_back(std::make_pair(v, w));
+        g[v].push_back(std::make_pair(u, w));
+    }
+
+    memset(f, 0xff, sizeof(f));
+
+    dfs(1, 0);
+
+    cout << f[1][k] << endl;
+
+    return 0;
+}