98. Graph Valid Tree

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Step 1 / 38

Speed: 1.0x

Graph Topology & Visited Memory

Visited

0

1

2

3

4

Adjacency List (Adj)

Edges Matrix

[0,1]

[0,2]

[0,3]

[1,4]

Algorithm Commentary

Step 1 of 38

Current Action

Start Graph Valid Tree validation. A valid tree must be connected and acyclic.

Variables

Current Node Contextnull

edges4

visited_size0

n5

resultnull

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Example 1:

Input: n = 5, edges = [[0,1],[0,2],[0,3],[1,4]]

Output: true

Explanation: The graph is connected and contains no cycles, forming a valid tree.

Example 2:

Input: n = 5, edges = [[0,1],[1,2],[2,3],[1,3],[1,4]]

Output: false

Explanation: The graph contains a cycle (1-2-3-1), so it's not a valid tree.

Example 3:

Input: n = 5, edges = [[0,1],[0,2],[0,3],[0,4]]

Output: true

Explanation: The graph is a star graph, connected and acyclic, hence a valid tree.

Example 4:

Input: n = 1, edges = []

Output: true

Explanation: A single node with no edges is a valid tree.

Example 5:

Input: n = 2, edges = [[0,1]]

Output: true

Explanation: Two nodes connected by one edge is a valid tree.

Example 6:

Input: n = 3, edges = [[0,1],[0,2],[1,2]]

Output: false

Explanation: Graph contains a cycle: 0-1-2-0

Constraints:

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Time Complexity

O(V + E)

Space Complexity

O(V + E)

98. Graph Valid Tree

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98. Graph Valid Tree

Understand Before Coding

Graph Topology & Visited Memory

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Draw Your Approach

Example 1:

Example 2:

Example 3:

Example 4:

Example 5:

Example 6:

Constraints:

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Use Cases

Graph Topology & Visited Memory

Current Action

Variables