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
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 

:D:
20110331 17:42:24
"The square of each cost value is less than 1,000,000". Both bounds are specified properly. 

Nikhil Garg:
20110331 17:42:24
Its weird but there are negative numbers in input. Not that its a problem, just that lower bound of vertex costs is not specified. 

.::Manish Kumar::.:
20110331 17:42:24
what would be answer for


ymGXX:
20110331 17:42:24
Be careful that there is a space between k and n in the output. 
Added by:  Omar ElAzazy 
Date:  20101130 
Time limit:  0.262s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ASM64 
Resource:  ACPC 2010 