Sphere Online Judge

SPOJ Problem Set (classical)

2530. Tiling a Grid With Dominoes

Problem code: GNY07H

We wish to tile a grid 4 units high and N units long with rectangles (dominoes) 2 units by one unit (in either orientation). For example, the figure shows the five different ways that a grid 4 units high and 2 units wide may be tiled.

Write a program that takes as input the width, W, of the grid and outputs the number of different ways to tile a 4-by-W grid.


The first line of input contains a single integer N, (1 ≤ N ≤ 1000) which is the number of datasets that follow.

Each dataset contains a single decimal integer, the width, W, of the grid for this problem instance.


For each problem instance, there is one line of output: The problem instance number as a decimal integer (start counting at one), a single space and the number of tilings of a 4-by-W grid. The values of W will be chosen so the count will fit in a 32-bit integer.



1 5
2 11
3 781

Added by:Marco Gallotta
Time limit:9.600s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel Pentium G860 3GHz)
Languages:All except: ERL JS NODEJS PERL 6 SCM chicken VB.net
Resource:ACM Greater New York Regionals 2007

hide comments
2015-02-13 08:45:32 Govind Lahoti
Awesome problem. Enjoyed solving it :)
2014-12-18 11:21:07 mayank
Tried after M3TILE. Almost similar. Could not get it straight though! :P
2014-07-01 19:25:33 fanatique
good one :)
2014-06-24 21:34:24 Ravi Shankar Mondal
100th green light :)
2014-05-26 17:18:19 Noob
Good one!
2014-01-30 06:33:30 Himanshu
Shouldn't input 3 give 5 + 2*5 - 1 = 14 as each tiling (except last) for input 2 can be widened by adding a column to the left or to the right.
2013-12-30 07:51:38 Ankit Kumar
my 50th on SPOJ :)
2013-12-23 21:29:38 Hitman
for n=0 ans=1
2013-05-13 23:36:37 nagato
what is the range of W??

Last edit: 2013-05-13 23:37:40
2013-03-01 11:07:06 Ouditchya Sinha
Easy Prob. 60s time limit? :D
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