Description:
Given a collection of numbers that might contain duplicates, return all possible unique permutations.
For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1].
Solution:
class Solution {
public:
vector<vector<int>> permuteUnique(vector<int>& nums) {
sort(begin(nums), end(nums));
vector<vector<int>> rc;
permute(rc, nums, 0);
return rc;
}
private:
void permute(vector<vector<int>>& result, vector<int> nums, int k) {
auto sz = (int)nums.size();
if (k >= sz-1) {
result.push_back(nums);
return;
}
permute(result, nums, k+1);
for (int i = k+1; i < sz; ++i) {
if (nums[i] != nums[k]) {
swap(nums[k], nums[i]);
permute(result, nums, k+1);
}
}
}
};
class Solution {
public:
vector<vector<int>> permuteUnique(vector<int>& nums) {
sort(begin(nums), end(nums));
vector<vector<int>> rc;
do {
rc.push_back(nums);
} while (next_permutation(begin(nums), end(nums)));
return rc;
}
};
转载于:https://www.cnblogs.com/deofly/p/permutations-ii.html
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