Permutations

Description

Given a collection of distinct integers, return all possible permutations.

Example:

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

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;
};