hdoj1021C

原题链接：hdoj1021

递归超时，，

#include<stdio.h>
int fun(int n);
int main()
{
    int n;
    while(scanf("%d",&n)!=EOF){
        if(fun(n)%3==0)
            printf("yes\n");
        else
            printf("no\n");
    }
    return 0;
}

int fun(int n)
{
    return n==0?7:(n==1?11:fun(n-1)+fun(n-2));
}

找规律…..AC

#include<stdio.h>
int main()
{
    int n;
    while(scanf("%d",&n)!=EOF){
        printf(n%4==2?"yes\n":"no\n");
    }
    return 0;
}