Insert Interval

题目地址：
https://leetcode.com/problems/insert-interval/#/description

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].

解题思路：
这道题就是先把没有重合的放到rst里面，然后开始把重合的部分new 成一个interval然后放到rst里面，然后把剩下的放到rst里面。

代码：

public List<Interval> insert(List<Interval> intervals, Interval newInterval) {
    List<Interval> rst = new ArrayList<Interval>();
    int i = 0;

    while(i < intervals.size() && intervals.get(i).end < newInterval.start){
        rst.add(intervals.get(i++));
    }

    while(i < intervals.size() && intervals.get(i).start <= newInterval.end){
        newInterval = new Interval(Math.min(newInterval.start, intervals.get(i).start), Math.max(newInterval.end, intervals.get(i).end));
        i++;
    }

    rst.add(newInterval);

    while(i < intervals.size()){
        rst.add(intervals.get(i++));
    }

    return rst;
}