uva 11069

一开始打了个表  发现 a[i] = a[i-3]+a[i-2];

#include <iostream>#include <fstream>#include <cstring>using namespace std;int n,a[100] = {0, 1, 2, 2};void init(){    for(int i = 4; i < 80; i++)        a[i] = a[i-3]+a[i-2];}int main(void){    init();    while(scanf("%d",&n) == 1)        printf("%d\n",a[n]);    return 0;}