https://www.hackerrank.com/challenges/acm-icpc-team/problem

ACM ICPC Team

#!/bin/python3

import sys
import collections

n,m = input().strip().split(' ')
n,m = [int(n),int(m)]
topic = []
topic_i = 0
for topic_i in range(n):
   topic_t = str(input().strip())
   topic.append(topic_t)
topics = collections.defaultdict(set)
pairs = []
for i in range(len(topic)):
    # Pick an item
    item, sublist = topic[i], topic[0:i]+topic[i+1:]
    length = len(sublist)
    for j in range(length):
        # Pick another item, thus comparing all combinations
        other = sublist[j]
        # Count the number of subjects the combination "knows"
        topic_bin = int(other, 2) | int(item, 2)
        topic_int = bin(topic_bin).count('1')
        # Since we're dealing with two lists, adjust the inner index to be 
        # the index of the same item in the outer index
        pair = i, j+1 if j >= i and j < length else j
        # Since indices are exclusive, make sure we're checking combinations and not permutations
        pair = (pair[0], pair[1]) if pair[0] < pair[1] else (pair[1], pair[0])
        # Obtain a hashable format for the indices
        pair = '%d.%d' % (pair[0], pair[1]), topic_int
        # Squirrell away the pair and their count of known topics for now
        pairs.append(pair)
for pair in pairs:
    # Using a set is arguably overkill but if we ever wind up with the same pair this avoids duplicates
    topics[pair[1]].add(pair[0])
most = max(topics.keys())
pairs = topics[most]
print('%d\n%d' % (most, len(pairs)))