46. Permutations

[Tcdian]

46. Permutations

给定一个 没有重复 数字的序列，返回其所有可能的全排列。

Example

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

[Tcdian]

Solution

• JavaScript Solution

/**
 * @param {number[]} nums
 * @return {number[][]}
 */
var permute = function(nums) {
    const result = [];
    const cache = new Set();
    backtracking();
    return result;

    function backtracking() {
        if (cache.size === nums.length) {
            result.push([...cache]);
            return;
        }
        for (let i = 0; i < nums.length; i++) {
            if (!cache.has(nums[i])) {
                cache.add(nums[i]);
                backtracking();
                cache.delete(nums[i]);
            }
        }
    }
};