Problem B - The Brick Stops Here
You have been hired by several clients of a factory that manufactures brass
bricks. Brass is an alloy of copper and zinc; each brick weighs 1000 grams,
and the copper content of a brick can range from 1 to 999 grams. (Note that
brass with less than 55% or more than 62% of copper is practically useless;
however, this is irrelevant for this question) The factory manufactures,
through various processes, different types of brick, each of which has a
different copper concentration and price. It distributes a catalog of these
types to its customers.
Your clients desire to buy a certain number (M) of bricks, which for,
uh, religious reasons must be of different types. They will be melted
together, and the resultant mixture must have a concentration of at least
CMin and at most CMax grams of copper per kilogram. Their goal
is to pick the M types of brick so that the mixture has the correct
concentration and the price of the collection is minimized. You must figure
out how to do this. M, CMin, and CMax will vary
depending on the client.
The first part of input consists of a line containing a number N
(1 <= N <= 200), the number of brick types, and then N
lines containing the copper concentration (between 1 and 999) and price
(in cents) of each brick type. No brick costs more than 10 dollars.
The second part consists of a line containing a number C (1 <=
C <= 100), the number of clients you are serving, followed by
C lines containing M (1 <= M <= 20),
CMin (1 <= CMin <= 999), and CMax (1 <=
CMax <= 999) for each client.
All input numbers will be positive integers.
Output consists of a line for each client containing the minimum possible
price for which they can purchase bricks to meet their demands. If there is
no way to match their specifications, output "impossible".
2 500 620
9 550 590
9 610 620