leetcode 合并区间

 1 /**
 2  * Definition for an interval.
 3  * public class Interval {
 4  *     int start;
 5  *     int end;
 6  *     Interval() { start = 0; end = 0; }
 7  *     Interval(int s, int e) { start = s; end = e; }
 8  * }
 9  */
10 public class Solution {
11     public List<Interval> merge(List<Interval> intervals) {
12         if(intervals.size()<=1) return intervals;
13         ArrayList<Interval> arry=new ArrayList<Interval>();
14         Comparator<Interval> cmp=new Comparator<Interval>(){
15             public int compare(Interval v1,Interval v2)
16             {
17                 return v1.start-v2.start;
18             }
19                 
20         
21             
22         };
23             Collections.sort(intervals,cmp);
24             Interval pre=intervals.get(0);
25             for(int i=1;i<intervals.size();i++)
26             {
27                 Interval cur=intervals.get(i);
28                 if(cur.start<=pre.end)
29                 {
30                   pre=new Interval(pre.start,Math.max(cur.end,pre.end));//merge
31                   
32                 }
33                 else
34                 {
35                     arry.add(pre);
36                     pre=cur;
37                 }
38                 
39             }
40             arry.add(pre);
41             return arry;
42            
43     }
44 }