1 vector<string> summaryRanges(vector<int>& nums) 2 { 3 int nums_len = nums.size(); 4 vector<string> res; 5 if (nums_len == 0) 6 return res; 7 8 for (int i = 0; i < nums_len;) { 9 int start = i, end = i; 10 while (end + 1 < nums_len && nums[end + 1] == nums[end] + 1) end++; 11 if (end > start) 12 res.push_back(to_string(nums[start]) + "->" + to_string(nums[end])); 13 else 14 res.push_back(to_string(nums[start])); 15 i = end + 1; 16 } 17 return res; 18 }