LC 898. Bitwise ORs of Subarrays

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We have an array?A?of non-negative integers.

For every (contiguous) subarray?B =?[A[i],A[i+1],...,A[j]]?(with?i <= j),we take the bitwise OR of all the elements in?B,obtaining a result?A[i] | A[i+1] | ... | A[j].

Return the number of possible?results.? (Results that occur more than once are only counted once in the final answer.)

class Solution {
public:
  int subarrayBitwiSEORs(vector<int>& A) {
    unordered_set<int> s;
    set<int> t;
    for(int i : A) {
      set<int> r;
      r.insert(i);
      for(int j : t) r.insert(j | i);
      t = r;
      for(int j : t) s.insert(j);
    }
    return s.size();
  }
};