499. Greatest Greatest Common Divisor
Time limit per test: 0.5
Memory limit: 262144
Andrew has just made a breakthrough in sociology: he realized how
to predict whether two persons will be good friends or not. It turns out that
each person has an inner friendship number
(a positive integer).
And the quality of friendship
between two persons is equal to the
greatest common divisor of their friendship number.
That means there are prime
people (with a prime friendship number)
who just can't find a good friend, and
Wait, this is irrelevant to
You are given a list of friendship numbers for several people. Find the highest
possible quality of friendship among all pairs of given people.
The first line of the input file contains an integer n
the number of people to process.
The next n
lines contain one integer each, between 1 and
(inclusive), the friendship numbers of the given people. All given friendship
numbers are distinct.
Output one integer — the highest possible quality of friendship.
In other words, output the greatest greatest common divisor among all pairs of
given friendship numbers.