LeetCode Summary Ranges

 1 public class Solution {
 2     public List<String> summaryRanges(int[] nums) {
 3         List<String> res = new ArrayList<String>();
 4         if(nums == null || nums.length == 0){
 5             return res;
 6         }
 7         
 8         int s = 0;
 9         int e = 0;
10         while(e<nums.length){
11             if(e<nums.length-1 && nums[e]==nums[e+1]-1){
12                 e++;
13             }else{
14                 if(s==e){
15                     res.add(String.valueOf(nums[s]));
16                 }else{
17                     String str = String.valueOf(nums[s]) + "->" + String.valueOf(nums[e]);
18                     res.add(str);
19                 }
20                 e++;
21                 s=e;
22             }
23         }
24         return res;
25     }
26 }