M3TILE - LATGACH3


In how many ways can you tile a 3×n rectangle with 2×1 dominoes?

Here is a sample tiling of a 3×12 rectangle.

Input consists of several test cases followed by a line containing -1. Each test case is a line containing an integer 0 ≤ n ≤ 30. For each test case, output one integer number giving the number of possible tilings.

Example

Input:
2
8
12
-1

Output:
3
153
2131

hide comments
sanskar_native: 2021-05-29 04:03:45

A classic DP + bitmask problem :)


Added by:psetter
Date:2009-02-17
Time limit:0.600s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ERL JS-RHINO NODEJS PERL6 VB.NET
Resource:ACM