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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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2018-04-01 05:38:46
AC in one go ! Only DFS 0.00sec |
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2018-03-28 18:34:38 sanjeev
solve it with dsu algorithm, you will get to know few things. |
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2018-03-19 06:57:59
Solved using BFS. Conditions to keep in mind are that n==m-1 for a tree. And whenever this holds true all the nodes must be connected so simply bfs :) |
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2018-02-04 05:35:59
DSU yolo |
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2018-02-01 15:35:12
0.01 ac!! :) |
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2018-01-29 02:54:21
Killed in one go ! Disjoint Set all the way ! |
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2018-01-23 20:06:24
SPOILER: dsu is much easier then dfs smh |
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2018-01-20 18:53:07
Keep in mind a tree must have n-1 edges & all the node will be connected. |
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2018-01-15 14:30:56
AC in one go... just check for cycles and whether each and every vertex is visited during DFS |
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2017-12-27 20:43:22
Adjacency list and dfs would work |
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