[LeetCode] Summary Ranges

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"].

Credits:
Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

Easy的题，要非常速度地写出bug free的代码！

class Solution {
public:
    vector<string> summaryRanges(vector<int>& nums) {
        vector<string> res;
        if (nums.empty()) return res;
        string s;
        int start = nums[0], end = nums[0];
        for (int i = 1; i <= nums.size(); ++i) {
            if (i < nums.size() && nums[i] == end + 1) {
                end = nums[i];
            } else {
                if (start == end) s = to_string(start);
                else s = to_string(start) + "->" + to_string(end);
                res.push_back(s);
                if (i < nums.size()) start = end = nums[i];
            }
        }
        return res;
    }
};