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
Zoro:
20140612 18:51:01
Try this.


rishabh sanklecha:
20140605 21:20:32
actually int is enough to solve the problem and we can solve this question without much knowledge of graph 

Soma:
20140603 09:36:56
can some one explain above test case?


Mohan K:
20140602 12:38:26
any tricky cases pl //


sarelfeniel:
20140422 08:55:50
Fun question. Bottleneck is input. 

AlcatraZ:
20140401 18:27:52
Finally AC.. numbers can b negative . Last edit: 20140401 18:28:56 

JordanBelfort:
20140209 16:02:02
no need for any extra array


Vipul Pandey:
20140127 13:56:34
problem is easy and nice. int is sufficient. No need of long long. 

shiva_hellgeek:
20140114 18:47:15
why usage of long long giving RTE!!!


sobhan:
20130720 21:14:51
i use dp and i got acc

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 