2026/05/10

[LeetCode] 46 Permutations

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class Solution {
private:
  int N;
  vector<bool> used;
  vector<vector<int>> ans;
  vector<int> cur;
  void dfs(int idx, vector<int> &nums) {
    if (idx == N) {
      ans.push_back(cur);
      return;
    }
    for (int i = 0; i < N; i++) {
      if (!used[i]) {
        used[i] = true;
        cur[idx] = nums[i];
        dfs(idx + 1, nums);
        used[i] = false;
      }
    }
  }

public:
  vector<vector<int>> permute(vector<int> &nums) {
    N = nums.size();
    ans.clear();
    cur.assign(N, 5566);
    used.assign(N, false);
    dfs(0, nums);
    return ans;
  }
};