(leetcode)Summary Ranges

 1 class Solution {
 2 public:
 3     vector<string> summaryRanges(vector<int>& nums) {
 4         vector<string> res ;
 5         if(nums.size()<1 ) return res;
 6         int i = 0;
 7         int n = nums.size();
 8         while(i<n)
 9         {
10             int j = 1;
11             while(i+j<n && nums[i] == nums[i+j]-j)    ++j;
12             res.push_back(j<=1?to_string(nums[i]):to_string(nums[i])+"->"+to_string(nums[i+j-1])); 
13             i = i + j;
14         }
15         return res;
16     }
17 };