SUBMERGE - Submerging Islands

Vice City is built over a group of islands, with bridges connecting them. As anyone in Vice City knows, the biggest fear of vice-citiers is that some day the islands will submerge. The big problem with this is that once the islands submerge, some of the other islands could get disconnected. You have been hired by the mayor of Vice city to tell him how many islands, when submerged, will disconnect parts of Vice City. You should know that initially all the islands of the city are connected.


The input will consist of a series of test cases. Each test case will start with the number N (1 ≤ N ≤ 10^4) of islands, and the number M of bridges (1 ≤ M ≤ 10^5). Following there will be M lines each describing a bridge. Each of these M lines will contain two integers Ui, Vi (1 ≤ Ui,Vi ≤ N), indicating that there is a bridge connecting islands Ui and Vi. The input ends with a case where N = M = 0.


For each case on the input you must print a line indicating the number of islands that, when submerged, will disconnect parts of the city.


3 3
1 2
2 3
1 3
6 8
1 3
6 1
6 3
4 1
6 4
5 2
3 2
3 5
0 0


hide comments
amstan: 2019-07-01 07:12:49

It's a simple articulation point problem but my code was failing on this test-case:

5 5
1 2
2 3
3 1
3 4
3 5
0 0

Correct Output : 1
My Output : 2

How did I correct this ?
Use boolean ap[] array to store which vertex is ap

kushwah121: 2018-06-29 09:05:52

My 100th !!!
Ac in one go with Ap!!

rajcoolaryan: 2018-06-20 12:33:47

AP and Ac....

aman_sachin200: 2018-06-17 15:39:34

Articulation Points!!! :P

ramini1996: 2018-02-10 20:44:32

AC in ONE GO !!! Learnt Tarjan's Algorithm for finding Articulation points :)

sharif ullah: 2017-11-23 08:49:24

this is straightforward AP problem,,,,if u getting WA ,then u just focus on ur implementation,,,,,
i got wa because
1.while calling DFS i just check condition and then increase counter of find ing AP,,,but i think this is wrong for my implementation,,,,cz,,,a node may count twice\
so,,,i just mark AP node in bolean array then, count AP.

Last edit: 2017-11-23 08:49:51
amulyagaur: 2017-10-30 06:32:48

Direct AP

spojabhi: 2017-10-19 21:59:45

I was also getting ans 3 in same test case but my code was accepted.
I think ans of toolkit was wrong.

smso: 2017-08-24 19:56:08

I tried to find the articulation points and was able to pass most of the test cases in spojtoolkit except the biggest one with N=10000 and M=3000 (answer=1222, mine=4).

Any hints?

namitp: 2017-07-16 09:21:53

Easy One...

Added by:Hector Navarro
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM64
Resource:MiniMaraton 2013 - UCV