1 files changed, 21 insertions, 0 deletions
diff --git a/Week05/Exercise21.cpp b/Week05/Exercise21.cpp
new file mode 100644
index 0000000..1572372
--- /dev/null
+++ b/Week05/Exercise21.cpp
@@ -0,0 +1,21 @@
+#include <iostream>
+
+int main() {
+    unsigned int n;
+    std::cin >> n;
+
+    unsigned long f1 = 1, f2 = 1, f3 = 1;
+    for (unsigned long i = 1; i <= 2 * n; i++) {
+        f1 *= i;
+        if (i <= n + 1)
+            f2 *= i;
+        if (i <= n)
+            f3 *= i;
+    }
+
+    unsigned long catalan = f1 / (f2 * f3);
+
+    std::cout << catalan << std::endl;
+
+    return 0;
+}