# Subdomain Visit Count Problem

## Description

LeetCode Problem 811.

A website domain “discuss.leetcode.com” consists of various subdomains. At the top level, we have “com”, at the next level, we have “leetcode.com”and at the lowest level, “discuss.leetcode.com”. When we visit a domain like “discuss.leetcode.com”, we will also visit the parent domains “leetcode.com” and “com” implicitly.

A count-paired domain is a domain that has one of the two formats “rep d1.d2.d3” or “rep d1.d2” where rep is the number of visits to the domain and d1.d2.d3 is the domain itself.

• For example, “9001 discuss.leetcode.com” is a count-paired domain that indicates that discuss.leetcode.com was visited 9001 times.

Given an array of count-paired domains cpdomains, return an array of the count-paired domains of each subdomain in the input. You may return the answer in any order.

Example 1:

``````1
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Input: cpdomains = ["9001 discuss.leetcode.com"]
Output: ["9001 leetcode.com","9001 discuss.leetcode.com","9001 com"]
Explanation: We only have one website domain: "discuss.leetcode.com".
As discussed above, the subdomain "leetcode.com" and "com" will also be visited. So they will all be visited 9001 times.
``````

Example 2:

``````1
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Input: cpdomains = ["900 google.mail.com", "50 yahoo.com", "1 intel.mail.com", "5 wiki.org"]
Output: ["901 mail.com","50 yahoo.com","900 google.mail.com","5 wiki.org","5 org","1 intel.mail.com","951 com"]
Explanation: We will visit "google.mail.com" 900 times, "yahoo.com" 50 times, "intel.mail.com" once and "wiki.org" 5 times.
For the subdomains, we will visit "mail.com" 900 + 1 = 901 times, "com" 900 + 50 + 1 = 951 times, and "org" 5 times.
``````

Constraints:

• 1 <= cpdomain.length <= 100
• 1 <= cpdomain[i].length <= 100
• cpdomain[i] follows either the “rep_i d1_i.d2_i.d3_i” format or the “rep_i d1_i.d2_i” format.
• rep_i is an integer in the range [1, 10^4].
• d1_i, d2_i, and d3_i consist of lowercase English letters.

## Sample C++ Code

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class Solution {
public:
vector<string> subdomainVisits(vector<string>& cpdomains) {
unordered_map<string, int> count;
for (auto cd : cpdomains) {
int i = cd.find(" ");
int n = stoi(cd.substr (0, i));
string s = cd.substr (i + 1);
for (int i = 0; i < s.size(); ++i)
if (s[i] == '.')
count[s.substr(i + 1)] += n;
count[s] += n;
}
vector<string> res;
for (auto k : count)
res.push_back(to_string(k.second) + " " + k.first);
return res;
}
};
``````