ABA12C - Buying Apples!

Harish went to a supermarket to buy exactly ‘k’ kilograms apples for his ‘n’ friends. The supermarket was really weird. The pricing of items was very different. He went to the Apples section and enquired about the prices. The salesman gave him a card in which he found that the prices of apples were not per kg. The apples were packed into covers, each containing ‘x’ kg of apples, x > 0 and ‘x’ is an integer. An ‘x’ kg packet would be valued at ‘y’ rupees. So, the placard contained a table with an entry ‘y’ denoting the price of an ‘x’ kg packet. If ‘y’ is -1 it means that the corresponding packet is not available. Now as apples are available only in packets, he decides to buy atmost ‘n’ packets for his ‘n’ friends i.e he will not buy more than n packets of apples.

Harish likes his friends a lot and so he does not want to disappoint his friends. So now, he will tell you how many friends he has and you have to tell him the minimum amount of money he has to spend for his friends.


The first line of input will contain the number of test cases, C.

Each test case will contain two lines.

The first line containing N and K, the number of friends he has and the amount of Apples in kilograms which he should buy.

The second line contains K space separated integers in which the ith integer specifies the price of a ‘i’kg apple packet. A value of -1 denotes that the corresponding packet is unavailable.

  • 0 < N <= 100
  • 0 < K <= 100
  • 0 < price <= 1000


The output for each test case should be a single line containing the minimum amount of money he has to spend for his friends. Print -1 if it is not possible for him to satisfy his friends.

Sample I/O

3 5
-1 -1 4 5 -1
5 5
1 2 3 4 5


Explanation of test cases:

1) As there are only 3 and 4kg packets in the shop, he will not be able to satisfy his friends as he would not be able to buy exactly 5kg of apples.

2) He can buy five 1kg packet as he has to buy 5 kg. So the min money he should spend is 5.

hide comments
tanavya: 2017-10-22 16:01:02

I don't know where people are getting the idea of disregarding N. Even if you get an AC by disregarding N, your solution is probably wrong. Try this test-case provided by cake_is_a_lie. Expected output is 8.

4 6
1 3 -1 -1 -1 -1

manish1997: 2017-10-20 02:39:14

Only Test cases are weak. Correct solution does get AC. Start solving problem rather than cursing setter. "n" is not useless. Try test case given by cake_is_a_lie on next page.

dwij28: 2017-09-23 23:57:42

Hands down one of the worst problem statements I have ever encountered.

pavan_kumar1: 2017-09-05 04:18:26

@admin Should he buy apple packs such that he distributes them among his friends equally?

sarwar95: 2017-08-07 17:09:36

what is use of dp in this qustion

sajib_only: 2017-08-01 16:06:06


1. prices can be 0.
2. n is useless. even considering it gives WA!
3. can take a packet several times.

shubham_9008: 2017-07-29 07:58:12

i don't get this whether he has to buy n packets or k kilos as in main question there in no mention of the variable k

deepika10: 2017-07-12 10:54:05

Ignore n. A nice variation of unbounded knapsack!

anurag31: 2017-07-03 09:53:34

DON'T consider 'n' and get AC...rest all is OK

aditya9125: 2017-07-02 12:03:15

O(n^3) solution passes!

Added by:Kashyap Krishnakumar
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM64
Resource:Own problem