Check whether adjacent next number exceeds previous number by 1 and continue until the difference is not 1. If a number with difference of 1 is found, the starting number won't be same as last number in a range.

```
vector<string> summaryRanges(vector<int>& nums) {
vector<string> vec;
int a;
int i=0, n=nums.size();
for(;i<n;i++){
a=nums[i];
while((i<n-1) && ((nums[i+1]-nums[i])==1)){
i++;
}
if(a!=nums[i]){
vec.push_back(to_string(a)+"->"+to_string(nums[i]));
}
else
vec.push_back(to_string(a));
}
return vec;
}
```