Check common element in tuples

[volcano63]

The best way to check for common elements is to use sets.

A proper solution would be a list of 3 values - since you compare 4 neighbours, but - taking your restraints into account.

from functools import reduce
tuples = [(45,50,30,21), (30,9,56,3), (56,10,21,4), (41,30,50,56)]
reduce(lambda res, pair: res+ [bool(set(pair[0]).intersection(pair[1]))],
      zip(tuples, tuples[1:]), [False])

Spelling it out in less golf-y way

def common_in_neigbours(tuples):
    result = [False]
    for left, right in zip(tuples, tuples[1:]):
        result.append(bool(set(left).intersection(right)))
    return result