HIGHWAYS - Highways

A number of cities are connected by a network of highways. Each highway is bidirectional and connects two cities, with a given travel time. What is the shortest time to get from a given city to another given city?


The first line of input contains the number of test cases.

Each test case starts with a line containing the number of cities n (2 ≤ n ≤ 100000), the number of highways m (1 ≤ m ≤ 100000), the starting city and the ending city. Cities are numbered from 1 to n.

Then m lines follow, each describing one highway. The description consists of the two distinct city numbers and the time in minutes to travel along the highway. The time will be between 1 and 1000.


For each test case output a single line containing the minimum time it takes to get from the start to the destination. If no connection exists, output NONE.


4 2 1 4
1 2 5
3 4 5
4 4 1 4
1 2 5
2 3 5
3 4 5
4 2 6


hide comments
ameyanator: 2018-04-25 08:46:20

My dijkstra with multiset runs in 0.04 secs. But how to solve with MST?

nilesh8757: 2017-10-20 21:38:58

Why my solution is not getting accepted. I mean , after clicking submit button ,it's not running.:(

sunny: 2017-08-14 21:53:49

AC in one Go :-). Dijkstra's.

marwankhaled: 2017-08-01 18:34:31

My 50th :D
First dijkstra

indra_5672: 2017-07-03 09:34:35

I solved it using dijkstra but i think we can solve it using mst because after finding mst we can find path between given nodes if it exists then it will be minimum time path. tell me if i am wrong @rohit9934 @admin @ nsitsk

rohit9934: 2017-06-14 19:54:37

AC in a go using Dijkstra.
How to do it with Minimum Spanning tree. Please help

code_aim: 2017-05-25 20:17:48

very weak test cases!!

testing java: 2017-01-14 14:24:48

@pd42slok as far as I know, you can't solve shortest path problem using an MST algorithm (such as kruskal). If i'm wrong, please feel free to enligh me. Otherwise, @admin - please correct the tag.

=(Francky)=> EB members are not responsible of the tags... They are posted by some psolvers, and can be sometimes spoil or wrong assert. You can choose option 'do not display tags' with your account.
Maybe one day, tag will be set by EB only, ...

Last edit: 2017-01-14 16:48:58
flyingduchman_: 2016-12-29 17:35:13

Dijkstra with priority-queue of STL ac .04s

lt: 2016-11-29 07:41:17

Dijkstra rocks. Done using sets!

Added by:Daniel Gómez Didier
Time limit:1s
Source limit:50000B
Memory limit:1536MB
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Resource:Circuito de Maratones ACIS / REDIS