ACPC10D  Tri graphs
Here’s a simple graph problem: Find the shortest path from the topmiddle vertex to the bottommiddle vertex in a given trigraph. A trigraph is an acyclic graph of (N ≥ 2) rows and exactly 3 columns. Unlike regular graphs, the costs in a trigraph are associated with the vertices rather than the edges.
So, considering the example with N = 4, the cost of going straight down from the top to bottom along the middle vertices is 7 + 13 + 3 + 6 = 29. The layout of the directional edges in the graph are always the same as illustrated in the figure.
Input
Your program will be tested on one or more test cases.
Each test case is specified using N + 1 lines where the first line specifies a single integer (2 ≤ N ≤ 100, 000) denoting the number of rows in the graph. N lines follow, each specifying three integers representing the cost of the vertices on the ith row from left to right. The square of each cost value is less than 1,000,000.
The last case is followed by a line with a single zero.
Output
For each test case, print the following line:
k. n
Where k is the test case number (starting at one,) and n is the least cost to go from the topmiddle vertex to the bottommiddle vertex.
Example
Input:
4
13 7 5
7 13 6
14 3 12
15 6 16
0
Output:
1. 22
hide comments
Sharan Girdhani:
20130626 09:23:32
Ac!! :D Last edit: 20130626 09:38:48 

Nishant Kumar:
20130621 15:13:59
easy one!!! 

aqfaridi:
20140122 23:59:58
Is it a question of graph ?? :P 

LaFolle:
20130520 19:09:40
int will be enough. 

aman gupta:
20130325 08:10:56
algo was easy, but implementation was quite painful :( but at last enjoyed a lot :) 

Rocker3011:
20130307 18:24:21
no need of long long :) easy problem 

Abo Hasan:
20130302 23:18:20
%lld with int costed me 3 WAs. Pay attention! 

Anmol:
20130114 12:24:39
initialisation are tricky


Haijun Deng:
20130114 02:56:32
Still WA with the following cases passed


abdou_93:
20130113 07:56:48
@janani the answer of

Added by:  Omar ElAzazy 
Date:  20101130 
Time limit:  1s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ASM64 
Resource:  ACPC 2010 