2026/05/08

[LeetCode] 57 Insert Interval

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class Solution {
public:
  vector<vector<int>> insert(vector<vector<int>> &intervals,
                             vector<int> &newInterval) {
    vector<vector<int>> ans;
    int newStart = newInterval[0];
    int newEnd = newInterval[1];
    int N = intervals.size();
    int i = 0;

    // step 1 : non-overlap left
    for (; i < N && intervals[i][1] < newStart; i++)
      ans.push_back(intervals[i]);

    // step 2 : merge overlap interval
    for (; i < N && intervals[i][0] <= newEnd; i++) {
      newStart = min(newStart, intervals[i][0]);
      newEnd = max(newEnd, intervals[i][1]);
    }
    ans.push_back({newStart, newEnd});

    // step 3 : non-overlap right
    for (; i < N; i++)
      ans.push_back(intervals[i]);

    return ans;
  }
};