Permutations

Problem Description

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 (JavaScript)

/**
 * @param {number[]} nums
 * @return {number[][]}
 */
var permute = function(nums) {
    const permu = (perm, left, rst) => {
        if(!left.length){
            rst.push(perm);
        } else {
            left.forEach((l, i) => {
                let newPerm = perm.slice();
                newPerm.push(l);
                let newLeft = left.slice();
                newLeft.splice(i,1)
                permu(newPerm, newLeft, rst);
            });
        }
    }
    
    let rst = [];
    permu([], nums, rst);
    return rst;
};