42. Permutations

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Input: nums = [1, 2, 3]

Output: [[1, 2, 3], [1, 3, 2], [2, 1, 3], [2, 3, 1], [3, 1, 2], [3, 2, 1]]

Explanation: All possible orderings of the numbers 1, 2, and 3 are generated.

Input: nums = [0, 1]

Output: [[0, 1], [1, 0]]

Explanation: All possible orderings of the numbers 0 and 1 are generated.

Input: nums = [1]

Output: [[1]]

Explanation: The only possible ordering of the number 1 is itself.

Time Complexity

O(n!)

Space Complexity

O(n)