commit 6eef81586890f940588aa53b2eabf19afbdb456c
Author: LittleSheep <littlesheep.code@hotmail.com>
Date:   Sun Apr 14 15:32:15 2024 +0800

    :white_check_mark: 选课 P2014

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a8a0dce
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*.bin
diff --git a/pick-class/main.cc b/pick-class/main.cc
new file mode 100644
index 0000000..7941063
--- /dev/null
+++ b/pick-class/main.cc
@@ -0,0 +1,53 @@
+#include <cstring>
+#include <iostream>
+using namespace std;
+
+const int MAXN = 300 + 5;
+
+typedef struct {
+  int left, right;
+  int score;
+} node;
+
+node tree[MAXN];
+int mem[MAXN][MAXN];
+int N, M;
+
+void insert(int current, int head) {
+  tree[current].right = tree[head].left;
+  tree[head].left = current;
+}
+
+int dfs(int node, int slots) {
+  if (node < 0 || !slots) {
+    return 0;
+  } else if (!node) { // Root node
+    return dfs(tree[node].left, slots);
+  }
+
+  if (mem[node][slots] > -1) {
+    return mem[node][slots];
+  }
+  mem[node][slots] = dfs(tree[node].right, slots); // When ignore this node
+  for (int i = 1; i <= slots; i++) {
+    int other = dfs(tree[node].left, i - 1) + dfs(tree[node].right, slots - i) +
+                tree[node].score;
+    mem[node][slots] = max(mem[node][slots], other);
+  }
+  return mem[node][slots];
+}
+
+int main() {
+  // Init
+  cin >> N >> M;
+  memset(tree, -1, sizeof tree);
+  memset(mem, -1, sizeof mem);
+  for (int i = 1; i <= N; i++) {
+    int depends, c;
+    cin >> depends >> c;
+    insert(i, depends);
+    tree[i].score = c;
+  }
+  // Calculating!
+  printf("%d", dfs(0, M));
+}
diff --git a/pick-class/main.in b/pick-class/main.in
new file mode 100644
index 0000000..d45ab7f
--- /dev/null
+++ b/pick-class/main.in
@@ -0,0 +1,8 @@
+7 4
+2 2
+0 1
+0 4
+2 1
+7 1
+7 6
+2 2