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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
| 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 |
hide comments
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2021-01-19 13:43:46
Try graphs like this one: 7 6 3 3 7 6 1 5 7 4 6 7 2 4 NO |
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2021-01-19 11:42:16
Keep the following edge cases in mind: 1 0 YES 0 0 NO |
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2020-10-16 19:55:17
For tree:- Number of connected components=1. Number of edges should be 1 less than number of vertices. These 2 conditions are enough to get AC:) |
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2020-10-02 13:48:36
just make sure to type YES and not Yes . i hate it |
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2020-09-24 23:29:07
AND WHAT IF I DONT? YOUR PROBLEMS ARE NOT MY PROBLEMS. |
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2020-09-22 05:04:52
GUYS LISTEN! FOR TLE -> USE ADJACENCY LIST NOT MATRIX. SIMPLE DFS WORKS AS A CHARM!! |
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2020-09-18 06:38:23
simple observation may help : 1 connected component and no cycle..:) |
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2020-09-05 11:31:00
i submitted two solutions 1st for directed and second for undirected.Both got accepted. |
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2020-08-19 10:37:15
easy disjoint set union problem |
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2020-08-18 13:53:43
simple dfs will do the the work |
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