LeetCode 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:
Given intervals [1,3],[6,9], insert and merge [2,5] in as [1,5],[6,9].

Example 2:
Given [1,2],[3,5],[6,7],[8,10],[12,16], insert and merge [4,9] in as [1,2],[3,10],[12,16].

This is because the new interval [4,9] overlaps with [3,5],[6,7],[8,10].

/**
 * 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> insert(vector<Interval> &intervals, Interval newInterval) {
		vector<Interval> ans;
		vector<Interval>::iterator it = intervals.begin();
		while (it != intervals.end()) {
			if (newInterval.end < it->start) {
				ans.push_back(newInterval);
				ans.insert(ans.end(), it, intervals.end());
				return ans;
			}
			else if (newInterval.start > it->end) {
				ans.push_back(*it);
			}
			else {
				newInterval.start = min(it->start, newInterval.start);
				newInterval.end = max(it->end, newInterval.end);
			}
			it++;
		}
		ans.insert(ans.end(), newInterval);
		return ans;
	}
};