Insert Interval

Given a non-overlapping interval list which is sorted by start point.

Insert a new interval into it, make sure the list is still in order and non-overlapping (merge intervals if necessary).

Have you met this question in a real interview? 

Yes

Example

Insert [2, 5] into [[1,2], [5,9]], we get [[1,9]].

Insert [3, 4] into [[1,2], [5,9]], we get [[1,2], [3,4], [5,9]].

用merge interval的方法做比较简单，先添加进去，然后思路参考merge interval 那道题就可以了。

代码：

public ArrayList<Interval> insert(ArrayList<Interval> intervals, Interval newInterval) {        ArrayList<Interval> result = new ArrayList<Interval>();        if(intervals == null ) return result;                intervals.add(newInterval);                Collections.sort(intervals, new Comparator<Interval>(){            @Override             public int compare(Interval o1, Interval o2){                return o1.start - o2.start;            }        });                        for(int i=1;i<intervals.size();i++){            if(intervals.get(i).start<=intervals.get(i-1).end){                merge(intervals,i-1, i);                i--;            }                    }        return intervals;    }        private void merge(List<Interval> intervals, int i, int j){        Interval i1 = intervals.get(i);        Interval i2 = intervals.get(j);        i1.end = Math.max(i1.end, i2.end);        intervals.remove(j);    }