LeetCode 90: Subsets II

LeetCode 90: Subsets II

Given a collection of integers that might contain duplicates, nums, return all possible subsets.

Note:

• Elements in a subset must be in non-descending order.
• The solution set must not contain duplicate subsets.

  For example,
  Ifnums =[1,2,2], A solution is:

  [  [2],  [1],  [1,2,2],  [2,2],  [1,2],  []]

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  This question has repeated elements, but in essence, it is similar to the question and can be handled in a similar way:

  Class Solution {public: vector
     
      
  > SubsetsWithDup (vector
      
       
  & Nums) {vector
       
        
  > Ans (1, vector
        
         
  (); Sort (nums. begin (), nums. end (); int pre_size = 0; for (int I = 0; I <nums. size (); I ++) {int n = ans. size (); for (int j = 0; j <n; j ++) // The second for loop is used to obtain all subsets containing nums [I] {if (I = 0 | nums [I]! = Nums [I-1] | j> = pre_size) {ans. push_back (ans [j]); // re-insert an existing subset of ans at the end. back (). push_back (nums [I]); // Add nums [I]} pre_size = n;} return ans ;}};