# 811. Subdomain Visit Count (M)

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:**

```
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:**

```
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 `"repi d1i.d2i.d3i"` format or the `"repi d1i.d2i"` format.
* `repi` is an integer in the range `[1, 104]`.
* `d1i`, `d2i`, and `d3i` consist of lowercase English letters.

### Solution:

```
class Solution {
    private Map<String,Integer> map;
    public List<String> subdomainVisits(String[] cpdomains) {
        
        this.map = new HashMap<>();
        
        for(int i = 0; i< cpdomains.length; i++)
        {
            getSubDomainCount(cpdomains[i]);
        }
        return getOutput(map);
    }
    
    public void getSubDomainCount(String element)
    {
        //String[] array = element.split(" ");
        String[] array = element.split("\\s+");
        int count = Integer.valueOf(array[0]);
        String domain = array[1];
        //重点在这里，"." 要用 "\\." 表示。
        String[] domains = domain.split("\\.");
        
        String temp = "";
        for(int i = domains.length-1; i>=0; i--)
        {
            temp = domains[i] + (temp.equals("") ? temp : "." + temp);
            map.put(temp, map.getOrDefault(temp, 0) + count);    
        }
    }
                    
    
    public List<String> getOutput(Map<String, Integer> map)
    {
        List<String> res = new ArrayList<String>();
        for(Map.Entry<String, Integer> entry : map.entrySet())
        {
            StringBuilder sb = new StringBuilder();
            sb.append(entry.getValue())
                .append(" ")
                .append(entry.getKey());
            res.add(sb.toString());
        }
        return res;
    }
                    
}
```

简易版：

```
class Solution {
    public List<String> subdomainVisits(String[] cpdomains) {
        Map<String, Integer> counts = new HashMap();
        for (String domain: cpdomains) {
            String[] cpinfo = domain.split("\\s+");
            String[] frags = cpinfo[1].split("\\.");
            int count = Integer.valueOf(cpinfo[0]);
            String cur = "";
            for (int i = frags.length - 1; i >= 0; --i) {
                cur = frags[i] + (i < frags.length - 1 ? "." : "") + cur;
                counts.put(cur, counts.getOrDefault(cur, 0) + count);
            }
        }

        List<String> ans = new ArrayList();
        for (String dom: counts.keySet())
            ans.add("" + counts.get(dom) + " " + dom);
        return ans;
    }
}
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://junnie.gitbook.io/nine-chapter/8.data-structure/811.-subdomain-visit-count-m.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.