LC 898. Bitwise ORs of Subarrays

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.)

Runtime: 652 ms

Memory Usage: 49.7 MB

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();

  }

};

巴特西

LC 898. Bitwise ORs of Subarrays

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