22. Graph DFS

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Input: graph = [[1, 2], [0, 3], [0, 3], [1, 2]], start = 0

Output: [0, 1, 3, 2]

Explanation: Starting from node 0, DFS visits its neighbor 1, then 1's neighbor 3, then backtracks to 0 and visits its neighbor 2.

Input: graph = [[1, 2], [0, 2], [0, 1]], start = 1

Output: [1, 0, 2]

Explanation: Starting from node 1, DFS visits its neighbor 0, then 0's neighbor 2.

Input: graph = [[], [], []], start = 0

Output: [0]

Explanation: Node 0 has no neighbors, so DFS only visits node 0.

Time Complexity

O(V+E)

Space Complexity

O(V)