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CSTREET - Cobbled streets |
The municipal chronicals of an unbelievable lordly major town in a land far, far away tell the following story:
Once upon a time the new crowned king Günther decided to visit all towns in his kingdom. The people of the unbelievable lordly major town expected that king Günther would like to see some of the most famous buildings in their town. For the lordly citizens it seemed necessary that all streets in the town that the king would have to use had to be cobbled with stone. Unfortunately the unbelievable lordly major town had not much money at that time as they used most of their savings to erect the highest cathedral the world had ever seen.
Rumours were afloat that the real reason for their thriftiness was not that the town treasury was empty but that many people believed that king Günther came to the throne by deceiving his father king Erwin and that in his youth he made a pact with the devil. But anyway, the citizens of the unbelievable lordly major town decided to pave only as much streets as were absolutely necessary to reach every major building.
Can you help the citizens of the unbelievable lordly major town to find out which streets should be paved?
It might be useful to know that all major buildings are either at the end of a street or at an intersection. In addition to that you can assume that all buildings are connected by the given streets.
Input
t [number of testcases (1 ≤ t ≤ 100)]
p [price to pave one furlong of street (positive integer)]
n [number of main buildings in the town (1 ≤ n ≤ 1000)]
m [number of streets in the town (1 ≤ m ≤ 300000)]
a b c [street from building a to building b with length c (lengths are given in furlong and the buildings are numbered from 1 to n)]
Output
For each testcase output the price of the cheapest possibility to reach all main buildings in the city on paved streets. You can assume that the result will be smaller than 232.
Example
Input: 1 2 5 7 1 2 1 2 3 2 2 4 6 5 2 1 5 1 3 4 5 2 3 4 3 Output: 12
Added by: | Simon |
Date: | 2005-05-24 |
Time limit: | 15s |
Source limit: | 32211B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All except: ERL GOSU JS-RHINO PERL6 |
Resource: | Ulm Algorithm Course SoSe 2005 |
hide comments
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2016-01-26 11:34:23
good one to practice algorithms :D but spoilers do reduce the beauty of the problem. |
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2015-12-25 19:24:04 kartikay singh
Piece of cake kruskal's mst + union-find -> AC 0.10s [EDIT]: union by rank and path-compression 0.09s Can be optimised with fast I/O ?. Last edit: 2015-12-26 07:58:33 |
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2015-10-16 22:50:53 anando_du
Normal MST . BTW don't know why time limit is 15s !! it should be 0.5 sec Last edit: 2015-10-16 22:52:24 |
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2015-06-22 05:19:31 sujit yadav
After learning kruskal algo and disjoint set ... its too easy :) AC |
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2015-05-24 06:41:08 bholagabbar
Yeah. Kruskal works even without Union by rank. However, I still keep getting 81.82 in the problem MST |
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2015-03-30 17:17:41 GAURAV CHANDEL
Good problem to learn MST and kruskal.. |
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2015-01-24 18:47:49 Ashish Sareen
Silly mistake cost me 2 WA :(. Kruskal is working fine |
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2015-01-18 22:14:33 Mayank Ladia
Green in one go.... easy one.. :) |
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2014-12-29 20:33:53 Francky
Time limit was 15s on Pyramid. |
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2014-12-29 20:18:08 (Tjandra Satria Gunawan)(曾毅昆)
I confirm what Jackson said, here is detail from my experiment: With path compression O(amortized:m) --> 0.04s Without path compression O(amortized:m*log(n)) --> 0.07s Most of time spend on processing huge I/O (I use scanf/printf for I/O). Time limit --> 15s on cube cluster. I suspect there are some misconfiguration. Is there anyone who remember time limit on this problem before cluster changed to cube? EDIT: I'll try with python.. Done: 0.89s @Francky: Thanks for the info, I'll remember this problem as it have "incorrect time limit", time limit should be arround 1.5s. Last edit: 2014-12-29 20:49:55 |