主題
class Solution
{
public:
vector<string> subdomainVisits(vector<string>& cpdomains)
{
unordered_map<string, int> c;
for (auto cd : cpdomains)
{
int i = cd.find(" ");//利用string的find()函式，找到空格的位子
int n = stoi(cd.substr (0, i));//std::stoi stoi函式可以將str中的數字轉成int
string s = cd.substr (i + 1, cd.size () - i - 1);//substr可以將字串拆開來讀取，這裡是讀取拆到空格" "後的字串
for (int i = 0; i < s.size(); ++i) if (s[i] == '.') c[s.substr(i + 1, s.size () - i)] += n;
c[s] += n;
}
vector<string> res;
for (auto k : c) res.push_back (to_string(k.second) + " " + k.first);
return res;
}
};
