46.Permutations

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

analyze

该问题可以看成为一道排列问题, 排列问题的一种常见解法是回溯法:

* 1
* 2
* 3
* 3
* 2
* 2
* 1
* 3
* 3
* 1
* 3
* 1
* 2
* 2
* 1
/**
* @param {number[]} nums
* @return {number[][]}
*/
var permute = function (nums) {
const res = []
backtracking(nums, [], res)
return res
};
var backtracking = function(nums, temp, res) {
if (temp.length === nums.length) {
res.push([...temp])
return
}
for (let i = 0; i < nums.length; i++) {
if (!temp.includes(nums[i])) {
temp.push(nums[i])
backtracking(nums, temp, res)
temp.pop(nums[i])
} else {
continue
}
}
}