【LeetCode】Merge Intervals

Given a collection of intervals, merge all overlapping intervals.

For example,
Given [1,3],[2,6],[8,10],[15,18],
return [1,6],[8,10],[15,18].

public class Solution {
    public ArrayList<Interval> merge(ArrayList<Interval> intervals) {
        if(intervals.isEmpty())
            return intervals;
        Collections.sort(intervals, new IntervalComparator());
        Interval pre = intervals.get(0);
        for(int i=1;i<intervals.size();i++){
            Interval temp = intervals.get(i);
            int start = pre.start;
            int end = pre.end;
            if(temp.start>end){
                pre=temp;
                continue;
            }else if(temp.start==end){
                pre.end=temp.end;
                intervals.remove(temp);
                i--;
                continue;
            }else{
                if(temp.start>=start&&temp.end>=end){
                    temp.start=start;
                    intervals.remove(pre);
                    pre = temp;
                    i--;
                    continue;
                    
                }else if(temp.start>=start&&temp.end<=end){
                    temp.start=start;
                    temp.end=end;
                    intervals.remove(pre);
                    pre=temp;
                    i--;
                    continue;
                }else if(temp.start<=start&&temp.end>=end){
                    intervals.remove(pre);
                    pre=temp;
                    i--;
                    continue;
                }else if(temp.start<=start&&temp.end>start&&end>temp.end){
                    temp.end=end;
                    intervals.remove(pre);
                    pre=temp;
                    i--;
                    continue;
                }
            }
        }
        return intervals;
        
    }
    
    
}
class IntervalComparator implements Comparator<Interval>
{
    public int compare(Interval a, Interval b) {
        return a.start - b.start;
    }
}