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
Shireen Nagdive: 2014-07-09 11:45:30

Can anyone give hints how to solve the code without dfs and bfs?

chin: 2014-07-05 16:20:30

getting seg fault..:(
Finally got AC..:D..got my mistake..

Last edit: 2014-07-07 04:56:16
Manu Narsaria: 2014-06-11 10:14:08

Submission ID:11738679
Please check it satisfies all possble input that i could find....

dragonemperor: 2014-05-26 06:40:47

Weak test case. In none of the cases, number of edges is less than number of vertices. I have a condition that checks if number of edges is less than number of vertices minus 1. If it satisfies, my code is not taking edges as input but I still got AC.

Suraj Rajan: 2014-05-20 22:09:10

cycles and connectedness..!! :)

Sudarshan K: 2014-04-23 20:18:04

My very first DFS problem. :)

sehwag: 2014-04-11 18:37:26

easyone...

Last edit: 2014-04-11 18:40:52
innovolt: 2014-04-11 13:03:18

gud1 nd easy1 simple dfs

Anubhav Balodhi : 2014-03-29 21:25:37

Easier than I thought... agreed with both the points of @Rastogi..

heatOn: 2014-03-17 11:59:31

No need for BFS or DFS !! easy one .


Added by:Thanh-Vy Hua
Date:2007-03-28
Time limit:0.5s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ERL JS-RHINO
Resource:Co-author Amber