'commit'

TangDou/Topic/Catanlan.cpp

@@ -0,0 +1,35 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+const int N = 20;
+
+// 学习视频
+// https://www.bilibili.com/video/BV1nE411A7ST
+int g[N];
+
+// f(0)*f(n-1)+f(1)*f(n-2)+....+f(n-1)*f(0)
+// 递归
+int f(int n) {
+    if (n <= 1) return 1;
+    int sum = 0;
+    for (int i = 0; i < n; i++)
+        sum += f(i) * f(n - 1 - i);
+    return sum;
+}
+
+int main() {
+    // 1、递推法
+    g[0] = g[1] = 1;
+
+    for (int i = 2; i < N; i++)
+        for (int j = 0; j < i; j++)
+            g[i] += g[j] * g[i - 1 - j]; // 考虑思路：画括号法
+
+    for (int i = 0; i < N; i++)
+        cout << g[i] << endl;
+
+    // 2 、递归法
+    for (int i = 0; i < N; i++)
+        cout << f(i) << endl;
+    return 0;
+}