P2014 [CTSC1997] 选课

R73521127

Luogu/P2014/P2014.cpp

@@ -0,0 +1,51 @@
+#include <cstring>
+#include <iostream>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 305;
+
+int n, m, s[N], f[N][N];
+std::vector<int> g[N];
+
+void dfs(int u) {
+    f[u][0] = 0;
+
+    for (int v : g[u]) {
+        dfs(v);
+
+        for (int i = m; i >= 0; i--) {
+            for (int j = i; j >= 0; j--) {
+                f[u][i] = std::max(f[u][i], f[u][i - j] + f[v][j]);
+            }
+        }
+    }
+
+    if (u) {
+        for (int i = m; i; i--) {
+            f[u][i] = f[u][i - 1] + s[u];
+        }
+    }
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    memset(f, 0xcf, sizeof(f));
+
+    cin >> n >> m;
+    for (int i = 1, x; i <= n; i++) {
+        cin >> x >> s[i];
+
+        g[x].push_back(i);
+    }
+
+    dfs(0);
+
+    cout << f[0][m] << endl;
+
+    return 0;
+}