2026/05/07

[LeetCode] 56 Merge Intervals

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class Solution {
public:
  vector<vector<int>> merge(vector<vector<int>>& intervals) {
    std::sort(intervals.begin(), intervals.end(),
      [](const vector<int>& v0, const vector<int>& v1) {
        if (v0[0] == v1[0])
          return v0[1] < v0[1];
        return v0[0] < v1[0];
      });
    vector<vector<int>> ans;
    int start = intervals[0][0];
    int end = intervals[0][1];
    for (int i = 1; i < intervals.size(); i++) {
      if (intervals[i][0] > end) {
        ans.push_back({start, end});
        start = intervals[i][0];
        end = intervals[i][1];
      }
      else {
        end = max(end, intervals[i][1]);
      }
    }
    ans.push_back({start, end});
    return ans;
  }
};