This PR adds a Java implementation to check whether a given undirected graph is a tree. It uses an adjacency matrix as input and applies Depth-First Search (DFS) to:

Detect cycles
Ensure the graph is fully connected

Key Points:

Input: number of nodes and adjacency matrix (1 → edge exists, 0 → no edge)
No self-loops allowed
Graph is a tree if:
No cycles exist
All nodes are reachable (i.e., graph is connected)

DSA Concept:
This problem falls under Graph Algorithms and uses DFS traversal for verification.

I have readCONTRIBUTING.md.
This pull request is all my own work -- I have not plagiarized it.
All filenames are in PascalCase.
All functions and variable names follow Java naming conventions.
All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
All new code is formatted withclang-format -i --style=file path/to/your/file.java

amankumar100 added2 commits

June 26, 2025 12:26

Create TreeCheck.java

908fd84

Added a Java program to check if an undirected graph is a tree using DFS and adjacency matrix. Verifies connectivity and absence of cycles.

added url

2464b15

amankumar100 requested review fromDenizAltunkapan,yanglbme,vil02,BamaCharanChhandogi,alxkm andsiriak ascode owners

June 26, 2025 07:09

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codecov-commenter commentedJun 26, 2025•
edited
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Codecov Report

Attention: Patch coverage is0% with33 lines in your changes missing coverage. Please review.

Project coverage is 74.03%. Comparing base(a8ad162) to head(9b35e09).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...in/java/com/thealgorithms/tree/GraphTreeCheck.java	0.00%	33 Missing⚠️

Additional details and impacted files

@@             Coverage Diff              @@##             master    #6318      +/-   ##============================================- Coverage     74.17%   74.03%   -0.15%  Complexity     5362     5362              ============================================  Files           678      679       +1       Lines         18686    18719      +33       Branches       3625     3636      +11     ============================================- Hits          13860    13858       -2- Misses         4272     4306      +34- Partials        554      555       +1

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