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1994-1995 ACM International Collegiate Programming Contest
Western European Regional
Mathematicians love all sorts of odd properties of numbers. For
instance, they consider 945 to be an interesting number, since it is
the first odd number for which the sum of its divisors is larger than
the number itself.
To help them search for interesting numbers, you are to write a
program that scans a range of numbers and determines the number that
has the largest number of divisors in the range. Unfortunately, the
size of the numbers, and the size of the range is such that a too
simple-minded approach may take too much time to run. So make sure
that your algorithm is clever enough to cope with the largest possible
range in just a few seconds.
The first line of input specifies the number N of ranges, and
each of the N following lines contains a range, consisting of
a lower bound L and an upper bound U, where
L and U are included in the range. L and
U are chosen such that (1 <= L <=U
<= 1,000,000,000) and (0 <= U-L <= 10,000).
For each range, find the number P which has the largest
number of divisors (if several numbers tie for first place, select the
lowest), and the number of positive divisors D of P
(where P is included as a divisor). Print the text
Between L and H, P has a maximum of
D divisors.', where L, H,
P, and D are the numbers as defined above.
Between 1 and 10, 6 has a maximum of 4 divisors.
Between 1000 and 1000, 1000 has a maximum of 16 divisors.
Between 999999900 and 1000000000, 999999924 has a maximum of 192 divisors.
Between 1500000 and 1510000, 1506960 has a maximum of 240 divisors.
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