Questions tagged [arrays]

A sequential random-access data structure whose size can typically not be changed after creation.

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Remove x last elements of an array and reinsert them before position y

I am looking for an algorithm to move a subarray in before an element (which is not part of that subarray) in the same array where the last element of the subarray is the last element of the array ...
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Sequential subsequence removal with arbitrary predicate

I want to extract sub-sequences from a sequence of float values. The "scale" and range of these values is arbitrary (as I can manipulate it at will) but the "shape" is consistent. For a visual ...
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Why is subarray $A[p..k-1]$ empty when $k=p$?

I'm working through a proof of correctness for merge sort. I'm given a loop invariant for a for loop, which makes reference to a subarray $A[p..k-1]$. During the initialization step of the ...
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Number of comparisons in array where each element appears n/k times [duplicate]

Given an array of $n$ elements with $k$ distinct elements, each appearing $n/k$ times, how can I show that the number of comparisons to the sort the array in the worst case is in $\Omega(n \log k)$?
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Thought process for the following problem?

We are given a 1-d array and we have to return the smallest array attainable after removing all the continuous same numbers. We can only eliminate those numbers which repeat continuously more than or ...
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Is it possible to write a fully-decidable type system for the J language?

I'm experimenting with the J array language, a dynamically-typed array language with mutable assignment, subtyping, and function overloading (just like traditional APL). It is unclear to me whether ...
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Check if two separate ranges have some number in common

We are given two permutations: A of size N and B of size M. We need to process Q queries, each query is given by two ranges, one subarray range in permutation A and one in B. We should check if there ...
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What is an array that can be iterated circularly an infinite amount of times called?

I have a feeling that the answer is either a "circular linked list" or a finite state machine, but the answer is probably a circular linked list.
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Minimum number of deleting palindromes to delete whole string

Let's say we have given array $A$ of size $n$. Our goal is to delete the whole array with minimum steps. In one step we can choose substring (consecutive elements from the string) and delete it only ...
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Finding maximum takes at least $\lceil n/2 \rceil$ comparisons

We are given an array $A$ with $n$ elements, $n \in \mathbb{N}$ and all elements are in the set $\{1,2,3, \cdots, n \}$. I want to prove that finding the maximum in $A$ (that is, outputting the index ...
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Min no.of operations required to convert an array to which it should contain elements of equal frequency

I have come across this tricky problem. An array of N elements should be converted to another array within k operations such ...
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Count the number of subsets with product less than or equal to k [closed]

You are given an array $A$ of $n$ positive integers, you have to find the number of subsets the product of whose elements is less than or equal to a given integer $k$. Is there an efficient algorithm ...
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Efficient algorithm to replace list of integers with nearest bigger element

The original question was in the context of an array, but I just used a list without changing the length for easier debugging purposes of toString(). Given an ...