s0509

src/s0509_fibonacci_number.cpp

@@ -0,0 +1,9 @@
+#include "s0509_fibonacci_number.hpp"
+
+int S0509::fib(int n) {
+  vector<int> dp{0, 1};
+  for (int i{2}; i <= n; ++i) {
+    dp.push_back(dp[i - 1] + dp[i - 2]);
+  }
+  return dp[n];
+}