leetcode 合并区间

使用最简单的排序方法；

 /**
  * Definition for an interval.
  * public class Interval {
  *     int start;
  *     int end;
  *     Interval() { start = 0; end = 0; }
  *     Interval(int s, int e) { start = s; end = e; }
  * }
  */
 public class Solution {
     public List<Interval> merge(List<Interval> intervals) {
         if(intervals.size()<=1) return intervals;
         ArrayList<Interval> arry=new ArrayList<Interval>();
         Comparator<Interval> cmp=new Comparator<Interval>(){
             public int compare(Interval v1,Interval v2)
             {
                 return v1.start-v2.start;
             }

         };
             Collections.sort(intervals,cmp);
             Interval pre=intervals.get(0);
             for(int i=1;i<intervals.size();i++)
             {
                 Interval cur=intervals.get(i);
                 if(cur.start<=pre.end)
                 {
                   pre=new Interval(pre.start,Math.max(cur.end,pre.end));//merge

                 }
                 else
                 {
                     arry.add(pre);
                     pre=cur;
                 }

             }
             arry.add(pre);
             return arry;

     }
 }