Elegant code: 1. string.join() 2. "{} {}".format(x, y)

811.subdomain-visit-count.py

# Time: O(n)
# Space: O(n)


# Before vs After 

#####################################
## After
#####################################
 

class Solution(object):
    def subdomainVisits(self, cpdomains):
        ans = collections.Counter()
        for domain in cpdomains:
            count, domain = domain.split()
            count = int(count)
            frags = domain.split('.')
            for i in xrange(len(frags)):
                ans[".".join(frags[i:])] += count  ## string.join()

        return ["{} {}".format(ct, dom) for dom, ct in ans.items()] # format 

#####################################
## Before
#####################################

from collections import defaultdict

class Solution(object):
    def subdomainVisits(self, cpdomains):
        """
        :type cpdomains: List[str]
        :rtype: List[str]
        """
        # init: hashmap
        ans = defaultdict(int)
        
        # interate 
        for each in cpdomains:
            count, domain = each.split(" ")
            count = int(count)
            element = domain.split(".") # 
            ans[domain] += count 
        
            left = ''
            for i in range(len(element)-1):
                left += element[i] + '.'
                temp = domain[len(left):]
                ans[temp] += count
        
        res = []
        for d,c in ans.items():
            format_ans = str(c) + " " + d
            res.append(format_ans)
            
        return res