poj2506

#include<stdio.h>
#include<string.h>
#define N 255
int f[N][N];
int main()
{
    int i,j,n;
    while(~scanf("%d",&n))
    {
        memset(f,0,sizeof(f));
        f[0][0]=1;
        f[1][0]=1;
        f[2][0]=3;
        if(n<=2)
        printf("%d\n",f[n][0]);
        else
        {
            int c=1;
            for(i=3;i<=n;i++)
            {
                int t=0;
                int s=0;
                for(j=0;j<c;j++)
                {
                    s=2*f[i-2][j]+f[i-1][j]+t;
                    f[i][j]=s%10;
                    t=s/10;
                }
                if(t)
                {
                    f[i][c]=t;
                    c++;
                }
            }
            for(i=c-1;i>=0;i--)
            printf("%d",f[n][i]);
            printf("\n");
        }
    }
    return 0;
}

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