Method fib

java/509_Fibonacci_Number.java:17–24

(int N)

    }

    public int fib(int N) {
        // Dp with memo, O(n)
        if (N < memo.size()) return memo.get(N);
        for (int i = memo.size(); i <= N; i++) {
            memo.add(memo.get(i - 1) + memo.get(i - 2));
        }
        return memo.get(N);
    }
}