285. 没有上司的舞会

https://www.acwing.com/problem/content/submission/code_detail/13122554/

AcWing/285/285.cpp

@@ -0,0 +1,50 @@
+#include <iostream>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 6005;
+
+int n, h[N], f[N][2], root;
+std::vector<int> g[N];
+bool vis[N];
+
+void dfs(int u) {
+    f[u][0] = 0;
+    f[u][1] = h[u];
+
+    for (int v : g[u]) {
+        dfs(v);
+        f[u][0] += std::max(f[v][0], f[v][1]);
+        f[u][1] += f[v][0];
+    }
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> n;
+    for (int i = 1; i <= n; i++) {
+        cin >> h[i];
+    }
+    for (int i = 1, l, k; i < n; i++) {
+        cin >> l >> k;
+        vis[l] = true;
+        g[k].push_back(l);
+    }
+
+    for (int i = 1; i <= n; i++) {
+        if (!vis[i]) {
+            root = i;
+            break;
+        }
+    }
+
+    dfs(root);
+
+    cout << std::max(f[root][0], f[root][1]) << endl;
+
+    return 0;
+}