Finding 3-Digit Even Numbers LeetCode solution in C++

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// Runtime: 4 ms, faster than 100.00% of C++ online submissions for Finding
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// 3-Digit Even Numbers. Memory Usage: 9 MB, less than 100.00% of C++ online
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// submissions for Finding 3-Digit Even Numbers.
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class Solution {
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 public:
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  vector<int> findEvenNumbers(vector<int> &digits) {
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    vector<int> ans;
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    int A[10] = {0}; // Array for 10 digits (0,1,2,3...)
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    for (auto &x : digits) A[x]++; // Fill our array
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    for (int i = 100; i < 999; i += 2) // Look through only correct numbers
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    {
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      int d1 = i / 100, d2 = i / 10 % 10, d3 = i % 10;
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      if (--A[d1] >= 0 & --A[d2] >= 0 & --A[d3] >= 0)
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        ans.push_back(i);        // Here we do 2 actions at the same time(we decrease all digits
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                                 // from our array A and also we check if after the decreasing we
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                                 // have enough digits in our array)
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      A[d1]++, A[d2]++, A[d3]++; // Refresh our array to start position
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    }
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    return ans;
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  }
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};