JAVA第16天——掌握递归杀器

• 话不多说，直接例子

• 开胃小菜

1. 递归求和

	public static int sum(int N) {
		if (N <= 0) {
			return 0;
		} // Of if

		return sum(N - 1) + N;
	}// Of sum

2. 斐波那契求和

	public static int sumfibonacci(int paraN) {
		if (paraN <= 0) {
			return 0;
		} 
		if (paraN == 1) {
			return 1;
		}//Of if
		
		return sumfibonacci(paraN - 1) + sumfibonacci(paraN - 2);
	}//Of sumfibonacci

• 终极BOSS

3. 汉诺塔

1. 有三根杆子A,B,C。A杆上有若干碟子
2. 每次移动一块碟子,小的只能叠在大的上面
3. 把所有碟子从A杆全部移到C杆上

    public static int hannoi(int N, char from, char inter, char to) {
    	int time = 0;
        if (N == 1) {
            System.out.println("Disk 1 from " + from + " to " + to);
            time += 1;
        }
        else {
            time += hannoi(N - 1, from, to, inter);
            System.out.println("Disk " + N + " from " + from + " to " + to);
            time += 1;
            time += hannoi(N - 1, inter, from, to);
        }
        return time;
    }// of hannoi