Leetcode之Insert Interval

题目：

Given a set of non-overlapping intervals, insert a new interval into the intervals (merge if necessary).

You may assume that the intervals were initially sorted according to their start times.

Example 1:

Input: intervals = [[1,3],[6,9]], newInterval = [2,5]
Output: [[1,5],[6,9]]

Example 2:

Input: intervals = [[1,2],[3,5],[6,7],[8,10],[12,16]], newInterval = [4,8]
Output: [[1,2],[3,10],[12,16]]
Explanation: Because the new interval [4,8] overlaps with [3,5],[6,7],[8,10]

代码：

class Solution {
public:
    vector<Interval> insert(vector<Interval>& intervals, Interval newInterval) {
        	vector<Interval> res;
	intervals.push_back(newInterval);

	if (intervals.size() == 1)return intervals;

	sort(intervals.begin(), intervals.end(), [](Interval &a, Interval& b) {return a.start < b.start; });
	
	int len = intervals.size();
	res.push_back(intervals[0]);

	for (int i = 1; i < len; i++) {
		if (res.back().end >= intervals[i].start) {
			res.back().end = max(res.back().end, intervals[i].end);
		}
		else {
			res.push_back(intervals[i]);
		}
	}

	return res;
    }
};

想法：结合以前学的知识点