The mook jong (HDU 5366)

The mook jong

Description


ZJiaQ want to become a strong man, so he decided to play the mook jong。ZJiaQ want to put some mook jongs in his backyard. His backyard consist of n bricks that is 1*1,so it is 1*n。ZJiaQ want to put a mook jong in a brick. because of the hands of the mook jong， the distance of two mook jongs should be equal or more than 2 bricks. Now ZJiaQ want to know how many ways can ZJiaQ put mook jongs legally(at least one mook jong).

 

Input

There ar multiply cases. For each case, there is a single integer n( 1 < = n < = 60)

 

Output

Print the ways in a single line for each case.

 

Sample Input

123456 

 

Sample Output

1235812 

题意：看输出，5=3+1+1，8=5+2+1，以此类推，a[i]=a[i-1]+a[i-3]+1,递归，推理。。。。。。
代码：
#include<stdio.h>
#include<string.h>
int main()
{
    long long a[2000];
    int n;
    while(~scanf("%d",&n))
    {
        a[1]=1,a[2]=2,a[3]=3;
        for(int i=4;i<=60;i++)
        {
            a[i]=a[i-1]+a[i-3]+1;   //递归。。。。。
        }
        printf("%lld\n",a[n]);
    }
}