P2015 二叉苹果树

R73420889

Luogu/P2015/P2015.cpp

@@ -0,0 +1,45 @@
+#include <iostream>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 105;
+
+int n, q, l[N], r[N], a[N], f[N][N];
+std::vector<std::pair<int, int>> g[N];
+
+void dfs(int u, int fa) {
+    for (auto e : g[u]) {
+        int v = e.first,
+            w = e.second;
+
+        if (v == fa) continue;
+        dfs(v, u);
+
+        for (int k = q; k; k--) {
+            for (int j = k - 1; j >= 0; j--) {
+                f[u][k] = std::max(f[u][k], w + f[u][k - j - 1] + f[v][j]);
+            }
+        }
+    }
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> n >> q;
+    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));
+    }
+
+    dfs(1, -1);
+
+    cout << f[1][q] << endl;
+
+    return 0;
+}