递归处理斐波那契数列

使用hashMap优化了结果

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

/**
 * @author zhangnianlei
 * @description
 * @date 2021/8/2
 */
public class Main {

    private static Map<Integer, Integer> feiMap = new HashMap<>();


    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNextInt()) {
            int m = sc.nextInt();
            System.out.println(fei(m));
        }
    }


    private static int fei(int m) {
        if (m == 0) return 0;
        if (m == 1) return 1;
        if (m == 2) return 1;
        Integer result = feiMap.get(m);
        if (result == null) {
            result = fei(m - 2) + fei(m - 1);
        }
        feiMap.put(m, result);
        return result;

    }

}