Permutations II
Given a collection of numbers, nums, that might contain duplicates, return all possible unique permutations in any order.
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Example 1:
Input: nums = [1,1,2]
Output:
[[1,1,2],
[1,2,1],
[2,1,1]]
Example 2:
Input: nums = [1,2,3]
Output: [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
Solution
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class Solution {
private:
set<vector<int>> mySet;
void permuteImpl(vector<int>& nums, int begin, int len) {
if (begin == len) {
return;
}
for (int i = begin; i < len; i++) {
swap(nums[begin], nums[i]);
mySet.insert(nums);
permuteImpl(nums, begin + 1, len);
swap(nums[begin], nums[i]);
}
}
public:
vector<vector<int>> permuteUnique(vector<int>& nums) {
int len = nums.size();
permuteImpl(nums, 0, len);
vector<vector<int>> ans;
for (auto item : mySet) {
ans.push_back(item);
}
return ans;
}
};
