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class Solution {
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 public:
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  vector<vector<int>> reconstructMatrix(int upper, int lower, vector<int> &colsum) {
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    vector<int> u, l;
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    vector<vector<int>> ans;
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    for (int i : colsum) {
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      if (i == 2) {
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        u.push_back(1);
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        l.push_back(1);
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        upper--;
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        lower--;
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      } else if (i == 0)
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        u.push_back(0), l.push_back(0);
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      else if (i == 1) {
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        if (upper >= lower) {
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          u.push_back(1);
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          l.push_back(0);
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          upper--;
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        } else {
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          u.push_back(0);
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          l.push_back(1);
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          lower--;
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        }
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      }
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    }
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    if (upper == 0 && lower == 0) {
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      ans.push_back(u);
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      ans.push_back(l);
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    }
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    return ans;
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  }
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};