PT07Y  Is it a tree
You are given an unweighted, undirected graph. Write a program to check if it's a tree topology.
Input
The first line of the input file contains two integers N and M  number of nodes and number of edges in the graph (0 < N <= 10000, 0 <= M <= 20000). Next M lines contain M edges of that graph  Each line contains a pair (u, v) means there is an edge between node u and node v (1 <= u,v <= N).
Output
Print YES if the given graph is a tree, otherwise print NO.
Example
Input: 3 2 1 2 2 3 Output: YES
hide comments
soumen_1696:
20200425 20:05:26
The main thing to remember to check weather tree >


yourmom__:
20200421 07:30:05
I heard people say that in java, Scanner is causing TLE. It's not true, as mine got accepted using Scanner. I used BFS. 

samio:
20200420 08:43:14
@sangmai, no it doesn't give TLE for recursive DFS. 

zoso_floyd:
20200415 09:43:55
Check if no_of_connected_components==1 && no_of_edges==N1; 

abhigurjeet:
20200319 11:17:03
learnt depth first search using adjacent list


pranjulpal18:
20200314 07:57:25
A simple DSU problem. 

sa03195100:
20200218 11:58:55
2


prithvi_3d2y:
20200206 16:14:54
SImple AC:


sangmai:
20200116 11:57:27
dfs with recursion gets TLE, use queue instead 

i_master:
20191230 23:00:07
Just think about it conceptually. What is a tree? A tree is a connected undirected acyclic graph.

Added by:  ThanhVy Hua 
Date:  20070328 
Time limit:  0.5s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JSRHINO 
Resource:  Coauthor Amber 