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
Ritesh Garg:
20120417 05:25:37
Please take care of the space after 1.<here>22 Last edit: 20120417 05:26:05 

bristy:
20120331 21:33:47
)P........ 

Andrew Cooper:
20120207 00:05:58
Woo hoo! Accepted first try. 

manish sharma:
20111214 18:42:34
Is "." is also included in the output 

Gregorius Edward:
20110814 05:37:31
so the input could be negative? 

Varun Kumar V:
20110706 03:41:42
use long long ints for output 

Jay Pandya:
20110629 05:37:47
no problem in dealing with negative numbers... and i think test cases may be 500 in a file.. 

NoszĂˇly Csaba:
20110625 10:48:08
:D said: "Both bounds are specified properly."


cegprakash:
20110408 03:46:18
testcases are awesome!!


BaLraM MaUryA:
20110331 17:42:24
finaly got acc... Last edit: 20110417 04:23:47 
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 