ACPC10D - Tri graphs

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Here’s a simple graph problem: Find the shortest path from the top-middle vertex to the bottom-middle vertex in a given tri-graph. A tri-graph is an acyclic graph of (N ≥ 2) rows and exactly 3 columns. Unlike regular graphs, the costs in a tri-graph 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.


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.


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 top-middle vertex to the bottom-middle vertex.


13 7 5
7 13 6
14 3 12
15 6 16

1. 22

hide comments
santamaria: 2016-09-07 14:52:55

That dot "." gives me *_* ... :(

mohamedshehata: 2016-09-02 14:52:22

Accepted recursive solution :D B| in one go ..

darkod3r: 2016-07-26 19:45:14

Easy one !! if u r getting WA, first check silly mistakes :D .. like i was printing just answer insted of testcase_no. and then answer. :P , costed me 2 WA :P

anuj0503: 2016-06-24 07:59:17

Top Down Runtime Error !!!
Bottom Up AC !! :)

surayans tiwari( 2016-06-15 11:38:21

test case are good

kshubham02: 2016-06-07 15:07:54

Easy DP :)

prateek1985: 2016-02-23 00:04:58

Java users do use fast i/o to get acc!!!

saini428: 2016-01-22 16:05:27

simple dp-

dokz: 2016-01-19 12:19:12

Simple dynamic for O(3 * n), just don't forget that you need to start from the MIDDLE top vertex, and some moves are impossible for the first two rows.

Utkarsh Agarwal: 2016-01-16 07:23:02

Issue with recursive solution ?? Itterative solution accepted .. Anybody with an accepted recursive soln ?

Added by:Omar ElAzazy
Time limit:0.262s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM64
Resource:ACPC 2010