EC_P  Critical Edges
This time I will not bore you with a long and boring sentence. Give a connected graph, you must find all the edges that are critical, in other words you must find the edges which when removed divide the graph.
Input
The first line contains a integer NC (1 ≤ NC ≤ 200), the number of test cases. Then follow NC test cases.
Each case begins with two integers N (1 ≤ N ≤ 700) and M (N1 ≤ M ≤ N * (N1) / 2), the number of nodes and the number of edges respectively. Then follow M lines, each with a pair of integers a b (1 ≤ a, b ≤ N) indicate that between the node a and the node b there is a edge.
Output
For each test case print the list of ways to protect the following format:
Caso # <n>
<t>
<x1> <y2>
<x2> <y2>
...
<xt> <yt>
Where n is the case number (starting from 1), t is the total of critical edges, list elements x_{i} y_{i} indicates, for each line, there is a critical edge between the node x_{i} and node y_{i} (1 ≤ x_{i} <y_{i} ≤ N). In addition, the list should be sorted in nodecreasing order first by x_{i} and then by y_{i}. Also x_{i} < y_{i} must hold.
If there isn't any critical edge print: "Sin bloqueos" (quotes for clarity).
Example
Input:3 5 4 1 2 4 2 2 3 4 5 5 5 1 2 1 3 3 2 3 4 5 4 4 6 1 3 1 4 2 1 3 2 4 2 4 3Output:Caso #1 4 1 2 2 3 2 4 4 5 Caso #2 2 3 4 4 5 Caso #3 Sin bloqueos
hide comments
aman_9899:
20170614 23:32:55
bridges in graph..!!!! 

Liquid_Science:
20160801 12:09:53
Very hard time limit for java :(


aspro:
20160603 18:42:57
good quetion....learned new concept....take care of o/p format 

bruzelee:
20160504 23:55:34
while saving the vector of pairs(saving the bridge edges in a data structure ) as u,v make sure you save u the minimum one out of two and v as the max one out of the two then apply the sorting algo and then print the ordered pair 

varun yadav:
20160129 21:53:02
Thx @Eddy Cael 

Pranay:
20140301 02:09:41
@Eddy : Could you please check why WA for id 11149094 ? Thanks. 
Added by:  Eddy Cael 
Date:  20131031 
Time limit:  0.100s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  CCLANG C CPP C++ 4.3.2 CPP14CLANG CPP14 JAVA PYTHON PYTHON3 