Questions tagged [lists]

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43 views

Lazy streams and infinite series

I just started Unix System Programming with Standard ML and starting on page 22 Shipman begins to explain a pure functional way of avoiding the constant state changes of typing at a keyboard: A ...
24 views

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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Lexicographic permutation list

Does anyone have an algorithm for stepping through all permutations of n given arbitrary objects in lexicographic order? Thanks.
185 views

The origin of list data structure

Does anyone know when the list data structure was mentioned in computer programming/algorithms? Who gave birth to this list concept?
75 views

Algorithm/data structure to quickly check if an integer is a member of any [lower, upper] interval

Are there any existing algorithms/strategies to test if an integer value is within the bounds of any of a list of intervals, where each interval is denoted by a [min, max] pair? The naive approach is ...
164 views

How to best maintain a sorted list from a stream of integers?

If I have an incoming stream of integers how can I best maintain a sorted list of them? The only way I can think of is to binary search for the position and shifting the remaining elements to the ...
39 views

Parallel Algorithm for Data Averaging

I am trying to write an efficient Parallelised algorithm for Data Averaging. By this I mean I have a list of tuples (K, V1, V2, V3) and in the end, I want a dictionary mapping K to the average of all ...
131 views

Can a list with $\mathcal{O}(1)$ access have an insertion complexity better than $\mathcal{O}(n)$?

It seems intuitive that there's no list data structure which has $\mathcal{O}(1)$ worst case time complexity for random access and a worst case complexity better than $\mathcal{O}(n)$ for insertion: ...
54 views

Insertion in 123 skip list

I had a problem in my exam dealing with 1-2-3 skip lists. I have a problem with the insertion process in a 1-2-3 skip list. What I understand is that if the minimum of heights of 2 nodes in a 123 ...
41 views

871 views

Why does linear search have $\frac{n}{2}$ comparisons on average?

I'm reading the Wikipedia page on Linear Search and it is mentioned that there are on average $\frac{n}{2}$ comparisons. I tried working this out on my own. First I considered the number of cases. ...
62 views

General name for linked lists based on hashes

I am thinking of a particular datastructure, but don't know the name of it. A sequence of elements may be modeled by a collection of some X, where each X consists of: The element, serialized as a ...
79 views

Partial intersection of 10 sorted lists of integers

Suppose I want to find the numbers that appear in at least 3 of the 10 sorted lists, is there an efficient way to do it apart from iterating over all 10 of them in parallel?
64 views

Expected Time for LookUpSkipList

A skip list Let C(k) = the expected length of the path that raises k levels backwards. Thus C(0) = 0 For any node P in the path, with k levels higher to go, there are two cases: P is a node of ...
98 views

Gauss-Jordan using stacks and list

I have a homework assignment in which I need to write an implementation of Gauss-Jordan with complete pivoting. Complete pivoting is a modification to the basic Gauss-Jordan algorithm in which rows ...
345 views

How to use structural induction to prove law on lists

I want to prove that the following equation holds using structural induction on (finite) lists ...
3k views

What's the fastest way to find the Kth smallest value in an unsorted list without sorting?

My initial algorithm: Compare element 0 with every other element, keeping track of how many elements are less than it. Repeat for each element until an element that is greater than exactly (k-1) ...
160 views

Efficiently finding duplicates in lists of numbers

I decided to try my hand at solving the knapsack problem. My idea involved generating $i$ tables, where $i: 1 \le i \lt n$, and each cell of an $i$ table contains one of the possible sums of the ...
1k views

Lambda calculus lists construction explanation

I have the following notes that introduce how lambda calculus handles lists. They go as follows: A list is something we can match on and deconstruct if it is not empty: ...
49 views

Description of lists with functions in LISP

I have been given the following implementation of basic list functions in LISP: ...
5k views

Find out duplicate number between 1 to N numbers

I first saw this question on this website where I was trying on Java puzzles. Here is the Question:- ...
53 views

Can randomization be proven?

There exists a collection c where c = {1, 2, 3} and a randomization of c, ...
46 views

Fastest way to Add and Subtract multiple parts of a List

I am doing some research where I have a List containing numbers. For example {5,10,98,22,13,15} What is a fast algorithm to calculate all possible sums and ...
3k views

The fastest algorithm for intersection of two sorted lists?

Say that there are two sorted lists: A and B. The number of entries in A and B can vary. (They can be very small/huge. They can be similar to each other/significantly different). What is the known ...
356 views

Skip List randomization complexity

I understand the basics of Skip Lists and their implementation also the basic Search Insert ...
355 views

Find the duplicates in a list of floating point numbers

I receive a list of real numbers ( float ) between $0$ and $1$. The list has length $N+1$ and I need to find two numbers on the list which are $\le \frac{1}{N}$ ...
78 views

Are there data structures that mix a tree structure with lists?

I suppose something like this could probably be easily designed, however I was wondering if there's a data structure that somehow uses both list and tree to access data. Something like this (I'll be ...
142 views

How can I get O(1) prepend on a random-access list?

I need a data structure that has the following operation: $\operatorname{prepend}([x_{n - 1}, ..., x_0], x_n) = [x_n, ..., x_0]$ $\operatorname{prepend}$ should be in $O(1)$. Assume that you have ...
94 views

How do I merge these lists?

I ave a a collection of lists of objects: $a_1$ $a_2$ $a_3$... $b_1$ $b_2$ $b_3$... $c_1$ $c_2$ $c_3$.. I need to merge them into a minimal possible number of lists, each list must be as long as ...
115 views

Algorithm for grouping identical neighbors in a list

I have a list that I want to reduce to a smaller list by grouping identical neighbors. This list has many many redundant entries. Example list: ...
254 views

How do I interpret this divide and conquer algorithm for removing duplicates in a list?

Consider the following divide and conquer algorithm to remove duplicates in a list. The text is in French. What is the meaning of the variables $c1, c2, d1, d2$? Why are only the variables $c1, d1$ ...
114 views

Is there a term for the general method used in XORed linked list?

The XOR linked list is perhaps the most prominent example of storing a reversible hash of two values and using a known value and the stored hash value to derive the other value. Is there a term for ...
22 views

Look for a pair of elements closest to two start positions in both directions until a condition is met

For a list which contains a set of elements I have two starting positions pos1and pos2 that are selected randomly. Next, I check ...
75 views

What is this GlueList Data Structure?

I came across a new list data structure called GlueList that claims faster than classic list implementations. How does it work ? How can it be faster than ArrayList and LinkedList ?
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Creating a list of minimum-distance pairs from two lists

Let's say there are two lists of objects, list1 and list2, and that there is a function that can generate the "distance" between an object in list1 and an object in list2. What I would like to do is ...