Daily LeetCode – day0068 0811. Subdomain Visit Count

// 0811. Subdomain Visit Count
class Solution {
    public List<String> subdomainVisits(String[] cpdomains) {
        HashMap<String, Integer> hashMap = new HashMap<>();
        for (String cpdomain : cpdomains) {
            String[] splitted = cpdomain.split(" ");
            int times = Integer.parseInt(splitted[0]);
            String domain = splitted[1];
            if (hashMap.containsKey(domain)) {
                hashMap.put(domain, hashMap.get(domain) + times);
            } else {
                hashMap.put(domain, times);
            }
            int len = domain.length();
            for (int i = 0; i < len; ++i) {
                if ('.' == domain.charAt(i)) {
                    String subdomain = domain.substring(i + 1, len);
                    if (hashMap.containsKey(subdomain)) {
                        hashMap.put(subdomain, hashMap.get(subdomain) + times);
                    } else {
                        hashMap.put(subdomain, times);
                    }
                }
            }
        }
        List<String> ans = new LinkedList<>();
        for (Map.Entry<String, Integer> entry : hashMap.entrySet()) {
            StringBuilder sb = new StringBuilder();
            sb.append(entry.getValue()).append(' ').append(entry.getKey());
            ans.add(sb.toString());
        }
        return ans;
    }
}

学习笔记：
这道题是哈希表统计数量的题目，不难，但巧妙的地方在于如何进行字符串的切割。