POLQUERY - Police Query

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To help capture criminals on the run, the police are introducing a new computer system. The area covered by the police contains N cities and E bidirectional roads connecting them. The cities are labelled 1 to N. The police often want to catch criminals trying to get from one city to another. Inspectors, looking at a map, try to determine where to set up barricades and roadblocks.

The new computer system should answer the following two types of queries:

1. Consider two cities A and B, and a road connecting cities G1 and G2. Can the criminals get from city A to city B if that one road is blocked and the criminals can't use it?

2. Consider three cities A, B and C. Can the criminals get from city A to city B if the entire city C is cut off and the criminals can't enter that city?

Write a program that implements the described system.


The first line contains two integers N and E (2 ≤ N ≤ 105, 1 ≤ E ≤ 5*105), the number of cities and roads. Each of the following E lines contains two distinct integers between 1 and N – the labels of two cities connected by a road. There will be at most one road between any pair of cities.

The following line contains the integer Q (1 ≤ Q ≤ 105), the number of queries the system is being tested on. Each of the following Q lines contains either four or five integers. The first of these integers is the type of the query – 1 or 2.

If the query is of type 1, then the same line contains four more integers A, B, G1 and G2 as described earlier. A and B will be different. G1 and G2 will represent an existing road.

If the query is of type 2, then the same line contains three more integers A, B and C. A, B and C will be distinct integers.

The test data will be such that it is initially possible to get from each city to every other city.


Output the answers to all Q queries, one per line. The answer to a query can be da (yes) or ne (no).


13 15
1 2
2 3
3 5
2 4
4 6
2 6
1 4
1 7
7 8
7 9
7 10
8 11
8 12
9 12
12 13
1 5 13 1 2
1 6 2 1 4
1 13 6 7 8
2 13 6 7
2 13 6 8


hide comments
vinty: 2020-04-01 20:20:18

Those whose answer fails at 10th test case , consider what would happen if the edge is a bridge but there is no need to cross it to reach b from a. Similarly the case when vertex is an articulation point but there is no need to cross it to reach b from a. Its simply not on the path.

nasif2587: 2019-08-22 13:46:48

The sample case has 5 queries. sample output has 4 outputs. and the current order of output is wrong as well. The setter need to correct it.

kanishk779: 2019-07-02 20:46:34

@vishal yes mine is also failing at 10th test case.

paroaro: 2018-07-16 15:10:33


Last edit: 2018-07-16 15:10:51
shahianshu: 2018-03-23 09:30:10

can anyone tell me that after query of type 1 do we keep the baracades on the road that we didn't use
and also if we remove c does this mean that c is removed permanenetly or just for that query it is not considered

linkret: 2016-07-06 01:10:13

yes @Youssef Ayman

Youssef Ayman: 2016-06-09 17:40:22

So should the output of the sample be

glaurung_666: 2016-04-29 22:21:54

some issue with sample output

vishal: 2014-12-29 18:20:55

anyone with .wa on 10th case.

Hussain Kara Fallah: 2014-02-08 05:04:48

I love this problem
It is perfect

Added by:~!(*(@*!@^&
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Resource:COI 08