leetcode summartRanges

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"].

解释来说就是给定一个数组，求它的范围总结

下面是本人的求解方式

class Solution {
public:
    vector<string> summaryRanges(vector<int>& nums) {
        vector<string> rangs;
        auto beg = nums.begin(), end = nums.end();
        vector<int>::iterator temp=beg;
        if (nums.size() == 0)return rangs;
        else{
            for (; beg != end-1;++beg){
                if (*beg+1 != (*(beg + 1)))
                {
                    
                    if (temp == beg)rangs.push_back(to_string(*temp));
                    else rangs.push_back(to_string(*temp) + "->" + to_string(*beg));
                    temp = beg + 1;
                }
            }
            if (temp == end - 1)rangs.push_back(to_string(*temp));
            else rangs.push_back(to_string(*temp) + "->" + to_string(*(end - 1)));
        }
        return rangs;
    }
};

求解范围时，必须知道下一个元素是否是上一个元素+1，如果是则不插入到rangs中去，如果不是则要插入进去。插入到rangs中要分两种情况，看是一个元素形成的范围，还是多个元素形成的范围