98. Graph Valid Tree

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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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