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SPOJ Problem Set (classical)

39. Piggy-Bank

Problem code: PIGBANK

Before ACM can do anything, a budget must be prepared and the necessary financial support obtained. The main income for this action comes from Irreversibly Bound Money (IBM). The idea behind is simple. Whenever some ACM member has any small money, he takes all the coins and throws them into a piggy-bank. You know that this process is irreversible, the coins cannot be removed without breaking the pig. After a sufficiently long time, there should be enough cash in the piggy-bank to pay everything that needs to be paid.

But there is a big problem with piggy-banks. It is not possible to determine how much money is inside. So we might break the pig into pieces only to find out that there is not enough money. Clearly, we want to avoid this unpleasant situation. The only possibility is to weigh the piggy-bank and try to guess how many coins are inside. Assume that we are able to determine the weight of the pig exactly and that we know the weights of all coins of a given currency. Then there is some minimum amount of money in the piggy-bank that we can guarantee. Your task is to find out this worst case and determine the minimum amount of cash inside the piggy-bank. We need your help. No more prematurely broken pigs!


The input consists of T test cases. The number of them (T) is given on the first line of the input file. Each test case begins with a line containing two integers E and F. They indicate the weight of an empty pig and of the pig filled with coins. Both weights are given in grams. No pig will weigh more than 10 kg, that means 1 <= E <= F <= 10000. On the second line of each test case, there is an integer number N (1 <= N <= 500) that gives the number of various coins used in the given currency. Following this are exactly N lines, each specifying one coin type. These lines contain two integers each, Pand W (1 <= P <= 50000, 1 <= W <=10000). P is the value of the coin in monetary units, W is it's weight in grams.


Print exactly one line of output for each test case. The line must contain the sentence "The minimum amount of money in the piggy-bank is X." where X is the minimum amount of money that can be achieved using coins with the given total weight. If the weight cannot be reached exactly, print a line "This is impossible.".


Sample Input:

10 110
1 1
30 50
10 110
1 1
50 30
1 6
10 3
20 4

Sample output:

The minimum amount of money in the piggy-bank is 60.
The minimum amount of money in the piggy-bank is 100.
This is impossible.

Added by:Adrian Kosowski
Time limit:5s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel Pentium G860 3GHz)
Languages:All except: SCM chicken
Resource:ACM Central European Programming Contest, Prague 1999

hide comments
2015-02-23 18:52:02 Abhay Mittal
My code got submitted on Codechef but is giving WA here. I can not understand the problem. Any help would be appreciated.

2015-02-04 11:43:21 Asheesh Pathak
Cleared it from my to-do list after a month...I think :D
2015-01-16 20:35:28 Ankur Singh
recursion with a table

Last edit: 2015-01-17 07:31:50
2014-11-25 12:20:01 Ankit Sultana
Don't forget the period at the end of each output!
2014-11-16 14:22:41 Malfple
the second testcase is simple: 1*100 = 100
2014-11-01 01:08:19 Prashant Jha

Last edit: 2014-11-01 01:09:02
2014-10-11 21:52:43 druid
KnapSack problem - DP Category

Last edit: 2014-10-11 21:52:58
2014-10-04 14:36:26 SHIVAM DIXIT
My same code gave tle and without modifications got accepted the next day..
12520218 gave tle and submission 12540812 got accepted the next day.. Will be grateful to anyone who can explain this inconsistency....Also it got accepted in 1.37 sec whereas time limit for this problem is 5 sec
2014-10-03 14:19:37 Monica
Sombody pls explain the 2nd test case. Shouldn't it be 330gm coin+ 10 1gm coins. Giving 50*3+10*1=160
2014-10-02 08:02:58 mayank
Unbounded knapsack! :D
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