vector<string> summaryRanges(vector<int>& nums) {

vector<string> result;

int n = (int)nums.size();

for (int left = 0, right = 0; right < n; left++, right++) {

while (right + 1 < n and nums[right + 1] == nums[right] + 1) {

right++;

}

int rangeLength = right - left + 1;

string range;

if (rangeLength == 1) {

range = to_string(nums[left]);

} else {

range = to_string(nums[left]);

range += "->";

range += to_string(nums[right]);

}

result.push_back(range);

left = right;

}

return result;

}