题解 | #合并区间#

排序：

/**
 * 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) {
        vector<Interval> ans;
        int n = intervals.size();
        // 以左边界大小排序
        sort(intervals.begin(), intervals.end(), [](Interval a, Interval b){return a.start < b.start;});
        for (int i = 0; i < n; ) {
            int l = intervals[i].start;
            int r = intervals[i].end;
            while (i < n-1 && intervals[i+1].start <= r) { // 如果左边界小于前一个右边界
                r = max(r, intervals[++i].end); // 更新右边界
            }
            ans.emplace_back(Interval(l, r)); // 记录合并区间
            i++;
        }
        return ans;
    }
};