Tiling

Description

In how many ways can you tile a 2xn rectangle by 2x1 or 2x2 tiles? 
Here is a sample tiling of a 2x17 rectangle. 

Input

Input is a sequence of lines, each line containing an integer number 0 <= n <= 250.

Output

For each line of input, output one integer number in a separate line giving the number of possible tilings of a 2xn rectangle. 

Sample Input

2
8
12
100
200

Sample Output

3
171
2731
845100400152152934331135470251
1071292029505993517027974728227441735014801995855195223534251

#include<stdio.h>
#include<string.h>
int ans[250][500];
int main()
{
    int n,i,j;
    while(~scanf("%d",&n))
    {
        memset(ans,0,sizeof(ans));
        ans[0][0] = 1;
        ans[1][0] = 1;
        ans[2][0] = 3;
        if(n <= 2)
            printf("%d\n",ans[n][0]);
        else
        {
            int cnt = 1,s,beyond;
            for(i = 3; i <= n; i++)
            {
                beyond = 0;
                for(j = 0; j < cnt; j++)
                {
                    s = ans[i-2][j]*2 + ans[i-1][j] + beyond;
                    ans[i][j] = s%10;
                    beyond = s/10;
                }
                if(beyond)
                {
                    ans[i][cnt] = beyond;
                    cnt++;
                }
            }
            for(i = cnt-1; i >= 0; i--)
                printf("%d",ans[n][i]);
            printf("\n");
        }
    }
    return 0;
}