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
xinnix: 2016-06-04 17:07:02

@codie 3kg packets are ₹4 and 4kg packets are ₹5. And rest packets are not available

Last edit: 2016-06-04 17:09:15
codie_905: 2016-06-01 15:19:56

Hi.. can somebody explain me in this test case
3 5
-1 -1 4 5 -1 - he can buy 5kg packet for 5 rupees, so why the answer for this one is -1?
and as per explanation 'As there are only 3 and 4kg packets in the shop' -- where is 3kg present in the shop, there are - '-1 -1 4 5 -1' not 3. please explain.. Thanks

sanjay: 2016-06-01 14:04:49

got AC with 2D and 1D as well.

sanjay: 2016-06-01 13:12:03

Didnt care N .Still got AC. can anyone post his solution who considered N in his/her solution to vsanjayvyas@gmail.com

vaibhavi760: 2016-05-19 22:34:42

Thanks mjguru for telling the role of n in the problem completely misunderstood the problem but still AC
A similar problem

Sonu Sharma: 2016-05-13 07:26:39

Varient of knapsack problem.Role of n in question is not mentioned but it is the same as stated in previous comments..

Last edit: 2016-05-13 07:27:08
surya_06: 2016-05-11 16:00:02

Test cases please ....

atif_11: 2016-05-09 23:59:39

Bingo...AC in 1st go and spend 4 hours

mjguru: 2016-04-20 12:04:59

Although the code 'might' work without using n, make sure that the you are able to solve this problem with the constraint of n as well. This is just a simple DP which is more closer to a variant of the unlimited knapsack problem.

subbu: 2016-04-18 14:06:21

nice explanation anup

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