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

 1 #include<stdio.h>

 2 #include<string.h>

 3 int ans[250][500];

 4 int main()

 5 {

 6     int n,i,j;

 7     while(~scanf("%d",&n))

 8     {

 9         memset(ans,0,sizeof(ans));

10         ans[0][0] = 1;

11         ans[1][0] = 1;

12         ans[2][0] = 3;

13         if(n <= 2)

14             printf("%d\n",ans[n][0]);

15         else

16         {

17             int cnt = 1,s,beyond;

18             for(i = 3; i <= n; i++)

19             {

20                 beyond = 0;

21                 for(j = 0; j < cnt; j++)

22                 {

23                     s = ans[i-2][j]*2 + ans[i-1][j] + beyond;

24                     ans[i][j] = s%10;

25                     beyond = s/10;

26                 }

27                 if(beyond)

28                 {

29                     ans[i][cnt] = beyond;

30                     cnt++;

31                 }

32             }

33             for(i = cnt-1; i >= 0; i--)

34                 printf("%d",ans[n][i]);

35             printf("\n");

36         }

37     }

38     return 0;

39 }

View Code