题解 | #合并区间#

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/**
 * Definition for an interval.
 * struct Interval {
 *     int start;
 *     int end;
 *     Interval() : start(0), end(0) {}
 *     Interval(int s, int e) : start(s), end(e) {}
 * };
 */
class Solution {
public:
    vector<Interval> merge(vector<Interval> &intervals) {
        sort(intervals.begin(), intervals.end(), [](const Interval& a, const Interval& b){
            if(a.start != b.start) return a.start < b.start;
            return a.end < b.end;
        });

        int n = intervals.size();
        if(n == 0) return {};
        vector<Interval> res;
        Interval inv(intervals[0].start, intervals[0].end);
        for(int i = 1; i < n; i ++){
            Interval itv = intervals[i];
            if(itv.start > inv.end){
                res.push_back(inv);
                inv.start = itv.start;
                inv.end = itv.end;
            }else{
                inv.start = min(inv.start, itv.start);
                inv.end = max(inv.end, itv.end);
            }
        }
        res.push_back(inv);
        return res;
    }
};