Merge Intervals

mergeIntervals.cpp

vector<vector<int>> mergeIntervals(vector<vector<int>>& intervals) {
    if (intervals.empty()) return {};
    sort(intervals.begin(), intervals.end());
    vector<vector<int>> res{intervals[0]};
    for (int i = 1; i < intervals.size(); ++i) {
        if (res.back()[1] < intervals[i][0]) { //doesn't overlap, push current interval
            res.push_back(intervals[i]);
        } else {
            res.back()[1] = max(res.back()[1], intervals[i][1]); //overlap, update end
        }
    }
    return res;
}