some programs!!

cs101/dh_04_01_fibonacci.cpp

@@ -0,0 +1,31 @@
+#include <iostream>
+#include <array>
+
+constexpr int MAX_N = 21;
+
+// 编译期生成斐波那契数列
+constexpr std::array<int, MAX_N> make_fib() {
+    std::array<int, MAX_N> fib{}; // 零初始化
+    fib[0] = 1;
+    fib[1] = 1;
+    for (int i = 2; i < MAX_N; ++i) {
+        fib[i] = fib[i - 1] + fib[i - 2];
+    }
+    return fib;
+}
+
+static constexpr auto fib = make_fib();
+
+int x;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    std::cin.tie(nullptr);
+
+    std::cin >> x;
+    while (std::cin >> x) {
+        std::cout << fib[x - 1] << std::endl;
+    }
+
+    return 0;
+}