hdu-2045 递归

标签：递归

#include <cstdio>
#include <iostream>
using namespace std;
long long a[55] = {0,3,6};
long long b[55] = {0,0,0,6};
long long int fun(int x);
long long int funa(int x);

long long int fun(int x){
	if(a[x]) return a[x];
	return a[x] = funa(x-1) * 2 + fun(x-1); 
}

 
long long int funa(int x){
	if(b[x]) return b[x];
	if(x <= 2) return 0;
	
	return b[x] = fun(x-1);
}
int main(){
	
	int n;
	fun(50);
	while(cin >> n){
		printf("%I64d\n",a[n]);
	}
	return 0;
	
}

hdu-2045 递归

标签：递归

原文地址：http://blog.csdn.net/qq_24667639/article/details/46830289