LeetCode-in-All

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

/**
 * @param {number[]} nums
 * @return {number[][]}
 */
var permute = function(nums) {
    if (!nums || nums.length === 0) {
        return []
    }

    const finalResult = []
    const used = new Array(nums.length).fill(false)

    const permuteRecur = (nums, finalResult, currResult, used) => {
        if (currResult.length === nums.length) {
            finalResult.push([...currResult])
            return
        }
        for (let i = 0; i < nums.length; i++) {
            if (used[i]) {
                continue
            }
            currResult.push(nums[i])
            used[i] = true
            permuteRecur(nums, finalResult, currResult, used)
            used[i] = false
            currResult.pop()
        }
    }

    permuteRecur(nums, finalResult, [], used)
    return finalResult
};

export { permute }

This site is open source. Improve this page.