LeetCode-46. Permutations

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问题描述

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

Example :

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

Constraints:

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

解答

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/*
 * @Description: 46. Permutations
 * @Author: libk
 * @Github: https://github.com/libk
 */
/**
 * @param {number[]} nums
 * @return {number[][]}
 */
const permute = function (nums) {
  const len = nums.length
  const res = []
  const path = []
  const used = new Array(len).fill(0)

  const backTrace = (depth) => {
    if (depth === len) {
      res.push(path.concat())
      return
    }

    for (let i = 0; i < len; i++) {
      if (!used[i]) {
        path.push(nums[i])
        used[i] = 1
        backTrace(depth + 1)
        used[i] = 0
        path.pop(nums[i])
      }
    }
  }

  backTrace(0)

  return res
}