Interval List Intersections LeetCode solution in C++

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class Solution {
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 public:
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  vector<vector<int>> intervalIntersection(vector<vector<int>> &firstList,
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                                           vector<vector<int>> &secondList) {
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    vector<vector<int>> result;
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    int i = 0;
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    int j = 0;
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    while (i < firstList.size() && j < secondList.size()) {
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      if ((firstList[i][0] >= secondList[j][0] && firstList[i][0] <= secondList[j][1]) ||
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          (secondList[j][0] >= firstList[i][0] && secondList[j][0] <= firstList[i][1])) {
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        // there is an overlap
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        result.push_back(
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            {max(firstList[i][0], secondList[j][0]), min(firstList[i][1], secondList[j][1])});
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      }
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      if (firstList[i][1] < secondList[j][1]) {
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        i++;
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      } else {
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        j++;
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      }
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    }
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    return result;
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  }
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};