【LeetCode】228 - Summary Ranges

Given a sorted integer array without duplicates, return the summary of its ranges.

For example, given [0,1,2,4,5,7], return ["0->2","4->5","7"].

My Solution:

vector<string> summaryRanges(vector<int>& nums)
    {
        vector<string> ret;
        if(nums.empty())return ret;
        int low=nums[];
        bool flag=false;
        for(int i=;i<nums.size();i++){
            while(i<nums.size() && nums[i]==nums[i-]+)i++;
            int high=nums[i-];
            if(low!=high)
　　　　　　　　　ret.push_back(to_string(low)+"->"+to_string(high));
            else
                ret.push_back(to_string(low));
            if(i==nums.size()){
                flag=true;
                break;
            }
            low=nums[i];
        }
        if(flag==false)ret.push_back(to_string(low));
        return ret;
    }

Better Solution:

 class Solution {
 public:
     vector<string> summaryRanges(vector<int>& nums) {
         vector<string> vec;
         if(nums.empty())
             return vec;

         int low=nums[],high=nums[];
         for(int i = ; i < nums.size(); i ++)
         {
             if(nums[i]-nums[i-] == )high=nums[i];
             else
             {
                 string range;
                 if(low != high)
                     range = to_string(low) + "->" + to_string(high);
                 else
                     range = to_string(low);
                 vec.push_back(range);
                 low = nums[i];
                 high = nums[i];
             }
         }
         string range;
         if(low != high)
             range = to_string(low) + "->" + to_string(high);
         else
             range = to_string(low);
         vec.push_back(range);
         return vec;
     }
 };