LeetCode 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"].

class Solution {
public:
vector<string> summaryRanges(vector<int>& nums) {
vector<string> ranges;
int len = nums.size();
if (len < 1) {
return ranges;
}
int start = 0;

for (int i=1; i<len; i++) {
if (nums[i] != nums[i-1] + 1) {
ranges.push_back(getRange(nums[start], nums[i-1]));
start = i;
}
}

ranges.push_back(getRange(nums[start], nums[len-1]));
return ranges;
}

string getRange(int start, int end) {
char buffer[32] = {0};
if (start == end) {
sprintf(buffer, "%d", start);
} else {
sprintf(buffer, "%d->%d", start, end);
}
return buffer;
}
};