codeup 课后习题 11.1 问题 A: Fibonacci

版权声明：原创文章，转载请注明出处 https://blog.csdn.net/hza419763578/article/details/88745217

问题 A: Fibonacci

时间限制: 1 Sec  内存限制: 32 MB
提交: 588  解决: 196
[提交][状态][讨论版][命题人:外部导入]

题目描述

The Fibonacci Numbers{0,1,1,2,3,5,8,13,21,34,55...} are defined by the recurrence: 
F0=0 F1=1 Fn=Fn-1+Fn-2,n>=2 
Write a program to calculate the Fibonacci Numbers.

输入

Each case contains a number n and you are expected to calculate Fn.(0<=n<=30) 。

输出

For each case, print a number Fn on a separate line,which means the nth Fibonacci Number.

样例输入

1

样例输出

1

#include<iostream>
using namespace std;
typedef long long ll;

const int N=120;//太大会溢出
ll dp[N]={0};
ll F(int n){
	if(n==0) return 0;
	if(n==1) return 1;
	if(dp[n]!=0) return dp[n];
	else{
		dp[n]=F(n-1)+F(n-2);
		return dp[n];
	}
}

int main(){
	int n;
	while(cin>>n){
		cout<<F(n)<<endl;
	}
	return 0;
}