811_subdomain-visit-count.py

# A website domain like "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.

# Now, call a "count-paired domain" to be a count (representing the number of 
# visits this domain received), followed by a space, followed by the address. 
# An example of a count-paired domain might be "9001 discuss.leetcode.com".

# We are given a list cpdomains of count-paired domains. We would like a list 
# of count-paired domains, (in the same format as the input, and in any order), 
# that explicitly counts the number of visits to each subdomain.

# Example 1:
# Input: 
# ["9001 discuss.leetcode.com"]
# Output: 
# ["9001 discuss.leetcode.com", "9001 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: 
# ["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.

# Notes:
#     The length of cpdomains will not exceed 100. 
#     The length of each domain name will not exceed 100.
#     Each address will have either 1 or 2 "." characters.
#     The input count in any count-paired domain will not exceed 10000.
#     The answer output can be returned in any order.

# ----------------------------------------------
# Ideas:

# Considerations: 

# Complexity: time, space
# ----------------------------------------------

class Solution:
    def subdomainVisits(self, cpdomains):
        """
        :type cpdomains: List[str]
        :rtype: List[str]
        """
        counts = {}
        for pair in cpdomains:
            count = int(pair.split(' ')[0])
            names = pair.split(' ')[1].split('.')
            for i in range(len(names)):
                domain = '.'.join(names[i:])
                counts[domain] = counts.get(domain, 0) + count    
        return ['{} {}'.format(c, d) for d, c in counts.items()]