解题思路:将数组先排序,然后用DFS遍历出所有的子集。
class Solution { public: void dfs(int d, vector<int>& nums, vector<int> cur, vector<vector<int>>& ans) { if (d >= nums.size()) { ans.push_back(cur); return; } int n = 1; while (d + n < nums.size() && nums[d] == nums[d+n]) n++; dfs(d + n, nums, cur, ans); for (int i = 1; i <= n; i++) { cur.push_back(nums[d]); dfs(d + n, nums, cur, ans); } } vector<vector<int>> subsetsWithDup(vector<int>& nums) { vector<vector<int>> ans; vector<int> cur; sort(nums.begin(), nums.end()); dfs(0, nums, cur, ans); return ans; } };