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46. Permutations

Medium

Given an array nums of distinct integers, return all the possible permutations. You can return the answer in any order.

Example 1:

Input: nums = [1,2,3]

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

Example 2:

Input: nums = [0,1]

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

Example 3:

Input: nums = [1]

Output: [[1]]

Constraints:

• 1 <= nums.length <= 6
• -10 <= nums[i] <= 10
• All the integers of nums are unique.

Solution

function permute(nums: number[]): number[][] {
    const result: number[][] = []
    const permuteRecursive = (nums: number[], index: number, result: number[][]) => {
        if (index >= nums.length) {
            result.push([...nums])
        }
        for (let i = index; i < nums.length; i++) {
            ;[nums[index], nums[i]] = [nums[i], nums[index]]
            permuteRecursive(nums, index + 1, result)
            ;[nums[index], nums[i]] = [nums[i], nums[index]]
        }
    }
    permuteRecursive(nums, 0, result)
    return result
}

export { permute }

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