P1040 [NOIP2003 提高组] 加分二叉树

R73670543

Luogu/P1040/P1040.cpp

@@ -0,0 +1,52 @@
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 35;
+
+int n, f[N][N], root[N][N];
+
+void dfs(int l, int r) {
+    if (l > r) return;
+
+    cout << root[l][r] << ' ';
+
+    if (l == r) return;
+    dfs(l, root[l][r] - 1);
+    dfs(root[l][r] + 1, r);
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> n;
+    for (int i = 1; i <= n; i++) {
+        cin >> f[i][i];
+        f[i][i - 1] = 1;
+        root[i][i] = i;
+    }
+
+    for (int len = 2; len <= n; len++) {
+        for (int l = 1, r = len; r <= n; l++, r++) {
+            f[l][r] = f[l][l] + f[l + 1][r];
+            root[l][r] = l;
+
+            for (int k = l + 1; k < r; k++) {
+                if (f[l][r] < f[l][k - 1] * f[k + 1][r] + f[k][k]) {
+                    f[l][r] = f[l][k - 1] * f[k + 1][r] + f[k][k];
+                    root[l][r] = k;
+                }
+            }
+        }
+    }
+
+    cout << f[1][n] << endl;
+
+    dfs(1, n);
+
+    cout << endl;
+
+    return 0;
+}