17 - All Unique Permutations of an array | GFG-POTD

17. All Unique Permutations of an array

The problem can be found at the following link:

My Approach

Sort the array in ascending order.
Generate all unique permutations using std::next_permutation.
Return the vector of unique permutations.

Time and Auxiliary Space Complexity

Time Complexity: O(N! * N), where N is the length of the array. This is because there are N! permutations, and for each permutation, it takes O(N) time to copy it.
Auxiliary Space Complexity: O(N!), where N is the length of the array. This is the space needed to store all unique permutations.

Code (C++)

class Solution {
  public:
    vector<vector<int>> uniquePerms(vector<int> &arr, int n) {
        sort(arr.begin(), arr.end());

        vector<vector<int>> out;
        do {
            out.push_back(arr);
        } while (next_permutation(arr.begin(), arr.end()));

        return out;
    }
};

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