import java.util.Map; import java.util.HashMap; class Main { public static void main(String[] args) { System.out.println(Fib3.fib3(40)); } private static class Fib3{ static Map<Integer, Integer> memo = new HashMap<>(Map.of(0,0,1,1)); private static int fib3(int n){ if(!memo.containsKey(n)){ memo.put(n, fib3(n-1) + fib3(n-2)); } return memo.get(n); } } }