斐波那契数列三种方法计算，光棍节快乐

Posted 2021-12-10 Roam-G

 //斐波那契数列三种方法计算
//Fibnacci(0)=0
//Fibnacci(1)=1
//Fibnacci(n)=Fibnacci(n-1)+Fibnacci(n-2)  [n>1]
//1.递归计算

 

 

//斐波那契数列三种方法计算
//Fibnacci(0)=0
//Fibnacci(1)=1
//Fibnacci(n)=Fibnacci(n-1)+Fibnacci(n-2)  [n>1]
//1.递归计算
long Fibnacci(long n) {
	if (n <= 1) return n;
	return Fibnacci(n - 1) + Fibnacci(n - 2);
};
//2.利用栈的非递归
struct Node {
	long n;//记忆走过的 n
	int tag;//区分 左右
};
long Fibnacci(long n) {
	Stack<T> S;
	Node* w;
	long  sum = 0;
	do {
		while (n > 1) {
			w->n = n;
			w->tag = 1;
			S.push(w);
			n--;
		}
		sum = sum + n;
		while (S.IsEmpty() == false) {
			S.Pop(w);
			if (w->tag == 1) {
				w->tag == 2;S.Push(w);n = w->n - 2;
				break;
			}
		}
	} while (S.IsEmpty() == false);
	return sum;
};
// 3.迭代
long Fibnacci(long n) {
	if (n <= 1)return n;
	long two = 0, one = 1, sum;
	for (int i = 2;i <= n;i++) {
		sum = two + one;
		two = one;
		one = sum;
	}
	return sum;
};