【LeetCode】228

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[0];
        bool flag=false;
        for(int i=1;i<nums.size();i++){
            while(i<nums.size() && nums[i]==nums[i-1]+1)i++;
            int high=nums[i-1];
            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:

 1 class Solution {
 2 public:
 3     vector<string> summaryRanges(vector<int>& nums) {    
 4         vector<string> vec;
 5         if(nums.empty())
 6             return vec;
 7     
 8         int low=nums[0],high=nums[0];
 9         for(int i = 1; i < nums.size(); i ++)
10         {
11             if(nums[i]-nums[i-1] == 1)high=nums[i];
12             else
13             {
14                 string range;
15                 if(low != high)
16                     range = to_string(low) + "->" + to_string(high);
17                 else
18                     range = to_string(low);
19                 vec.push_back(range);
20                 low = nums[i];
21                 high = nums[i];
22             }
23         }
24         string range;
25         if(low != high)
26             range = to_string(low) + "->" + to_string(high);
27         else
28             range = to_string(low);
29         vec.push_back(range);
30         return vec;
31     }
32 };