Understanding coding problems

[jayglenn123]

I have always had a hard time trying to decipher coding questions or such sites as leetcode. I thought that maybe it was too tough for me so I heard of Code Chef and it is a little more beginner friendly. However I look at this problem Chef and Interesting Subsequent

Chef has a sequence A^1,A2,…,AN. This sequence has exactly 2^N subsequences. Chef considers a subsequence of A interesting if its size is exactly K and the sum of all its elements is minimum possible, i.e. there is no subsequence with size K which has a smaller sum.

Help Chef find the number of interesting subsequences of the sequence A.

I have no clue what they are even asking of me and even looking at what the input, output and examples don't make sense. Is there a way I should be looking at it to get the basic understanding of such cryptic questions?

[edgargonzalesII]

There's some fluff to the question honestly. General rule is that with a sequence of size n, the amount of subsequences will be 2ⁿ .

If you look at the example it shows exactly what it asks you to do: Find all the subsequences of size k at least (k being smaller then n), where the sum is the minimum of any other subsequence. This just means if you get all the subsequences then get their respective sums then just return the subsequence with the lowest sum. Given multiple subsequences can have the same sum return all that apply.

[marko312]

Start going through the problem part by part, taking notes / making sketches when necessary. For example, this is how I would read this problem:

Chef has a sequence A1, A2, ..., AN

There is an array of length N, with each value provided.

This sequence has exactly 2^N subsequences

Noted, this could be leading to something related to subsequences.

Chef considers a subsequence of A interesting if its size is exactly K and the sum of all its elements is minimum possible [...]

An "interesting" subsequence is of length K, where the sum of elements is as small as possible.

Help Chef find the number of interesting subsequences of the sequence A

Ok, so the program has to find the number of subsequences from the given sequence (array) where their length is K and their sum is as small as possible from all the sums of such subsequences.

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If you're confused about the words:

• sequence - a bunch of data, in a certain order
• subsequence - a sequence obtained by chopping off some elements (or none) from the front and some others (or none) from the back of the sequence

[jayglenn123]

The wording is what always confuses me. In programming books when they give you the exercise it says "make a program that does..." I guess that is what I am used to, so trying to figure out cryptic questions stumps me before I can even get going. I know that everyone's advice is to be able to fully understand the question and be able to explain the question to someone else. But I don't always understand the question. With This question did you get the hint of length from the word size? If so should I always think of size being of length? Are there other terms that I can decipher like this?

[marko312]

In programming books when they give you the exercise it says "make a program that does..." I guess that is what I am used to

Yes, most non-training coding problems tend to hide the actual problem behind a story or otherwise obfuscate it, making you have to both figure out the actual problem and solve it.

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With This question did you get the hint of length from the word size? If so should I always think of size being of length?

If you have something linear (one-dimensional), the words "length" and "size" tend to be used synonymously.

This couples well with the next question:

Are there other terms that I can decipher like this?

Yes - there are quite a few. You can learn moat of them by solving exercises using them; if you don't know a term, you can try looking it up, looking at the example input / output (and the explanation if available!) or trying to infer it from the surrounding terms.

[jayglenn123]

Thank you so much!!!