花花酱 LeetCode 46. Permutations

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: DFS

Time complexity: O(n!)
Space complexity: O(n)

// Author: Huahua

class Solution {

public:

vector<vector<int>> permute(vector<int>& nums) {

const int n = nums.size();

vector<vector<int>> ans;

vector<int> used(n);

vector<int> path;

function<void(int)> dfs = [&](int d) {

if (d == n) {

ans.push_back(path);

return;

}

for (int i = 0; i < n; ++i) {

if (used[i]) continue;

used[i] = 1;

path.push_back(nums[i]);

dfs(d + 1);

path.pop_back();

used[i] = 0;

}

};

dfs(0);

return ans;

}

};

请尊重作者的劳动成果，转载请注明出处！花花保留对文章／视频的所有权利。
如果您喜欢这篇文章／视频，欢迎您捐赠花花。
If you like my articles / videos, donations are welcome.

Buy anything from Amazon to support our website
您可以通过在亚马逊上购物（任意商品）来支持我们

Paypal

Venmo
huahualeetcode

微信打赏