Questions tagged [hash-map]
A data structure that uses a hash function to map identifying values, known as keys, to their associated values
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Dictionary<TKey, TValue> Implementation
This class encapsulates a List<KeyValuePair> (see List<T> implementation here, and ...
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Genericizing PropertyValues
This should be the last iteration for this code.
Does this approach make sense or am I heading down the wrong path?
The only thing I can see to make this better is to genericize the ...
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LeetCode 49: Group Anagrams
I'm exceeding the time limit for a 10,000 word test case provided on LeetCode:
Given an array of strings, group anagrams together.
For example, given: ...
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IndexedArray Class: Uses a Dictionary Keys to Index a 2 Dimensional Array of Values
This class encapsulates a 2D Array and a Scripting Dictionary. Values are add or returned from to the Array using a Key and a ColumnIndex, e.g. ...
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Traversing and printing complex Dictionary types (Scripting.Dictionary) - Dictionary inside of a Dictionary
Based on this SO post - also reposted on vba4all.com with a few more details and explanations.
Please notice there currently is no error handling whatsoever as I didn't analyse and consider any traps ...
user28366
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Unicode-capable symbol table (N-way search tree with hash buckets)
As in my previous question, this module is coupled with its own testing framework.
As a symbol-table for a Unicode-capable programming language interpreter, I decided to combine the 3 types of ...
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Hackerrank challenge - Dictionaries and Maps
This is a solution for the Day 8 hackerrank.com challenge. The basic idea of the challenge is to create a mapping of names to phone numbers based on the the given input, and later look up the phone ...
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Preparing tabular data to be sent as json
I query a database and pass the data for processing as a DataTable. After all computations (grouping, filtering, formatting etc.) I need to send it to a Web-Service ...
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A simple Java integer hash set - follow-up
(See the previous version.)
(See the next version.)
After incorporating changes in the previous post, I came up with this implementation. However, I left hashing as it is.
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Type-safe Dictionary for various types
Assume the following situation: you have an object that can store any object based on a key (basically, IDictionary<string, object>). You want to store ...
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Mapping arbitrary Int values to a linear index space
This is part of a growing "primitive" tools collection here on github, and is the initial use-case for the IntArray for review here.
Often, when processing data, you encounter unique values that you ...
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Python Dictionary Black Magic
I am defining a subclass of a the python dictionary object mpCmd where every item is converted to a lambda. The intended usage is that every item in the dictionary ...
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Python Hash Table Implementation
I'm attempting to implement a basic hash table in Python using only lists. Any tips would be appreciated (including better hash functions).
I intend this to handle collisions with separate chaining.
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Simple trie implementation in JavaScript
After experimenting with a sorted trie implementation in C, I felt that I understood tries pretty well, but was having trouble explaining how they work. Since the C code was based on existing code, I ...
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Codewars: Reduce strings to one character
I am trying to solve a puzzle in a performant way. This is the puzzle.
Simply explained: you have a String and you must reduce it to one character with the given rules. This is the solution to the ...
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Extraction of value from a dict-tree, given a path of arbitrary length
Problem: We read a complex json-file which grants us a tree in terms of a python "dict of dicts". We're then requested to retrieve a specific path from the tree, represented by a list of elements. The ...
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iterating over the values of a list of ordered dictionaries
I am facing the following problem: I have a special data structure that is a dictionary whose keys are integers (dimensions). The values are also dictionaries whose keys are strings (geometric types) ...
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Yet another hash table in C
Will be very grateful for thoughtful code review.
I needed hash table (again) and I wrote one. Code here is here or inline:
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An interval-map data structure
This data structure maps values from intervals of some type Key which satisfies LessThanComparable<Key> to values of some ...
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Bidirectional Dictionary
The management of bidirectional mappings is a reoccuring topic. I took the time to write an (hopefully) efficient implementation.
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Calculating protein mass
This question is part of a series solving the Rosalind challenges. For the previous question in this series, see A sequence of mistakes. The repository with all my up-to-date solutions so far can be ...
Mast♦
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HackerRank "Ransom Note" challenge
I have solved the Ransom Note
challenge on HackerRank using JavaScript / ECMAScript 6. The challenge goes like this:
A kidnapper wrote a ransom note but is worried it will be traced back to him. He ...
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Calculating effective shop inventories from CSV files
Program purpose
The purpose for the program is to create a file containing the effective inventory for each stocked item stored in a collection of shops.
Input and algorithm details
For clarity, ...
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Bidirectional bijective hash map in C
I have this bidirectional hash map in C for dealing with bijective maps. Each key mapping consists of a primary key and a secondary key, and I can ask the data structure to give me a secondary key ...
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Agent-based Immutable Map
I am in the process of removing the last few pieces of mutable state from an F#-based distributed system. Some of the remaining mutable state is a ...
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Generic NSMapTable replacement written in Swift
This is my attempt at writing a generic NSMapTable with weak keys and strong values (after your feedback I'll be trying to write Strong-Key/Weak-Value and Weak-Key/...
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InfixDictionary: Data structure for Infix string lookup
I needed a data structure to quickly find all previously inserted values, that have the given string as key or substring (full text search).
At first, I tried out some tree structures (infix trie/...
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The most efficient way to merge two lists in Java
I am looking for a way to merge two files with a list of distinct words, one word per line. I have to create a new txt file that would contain all the words of the first list and all the words from ...
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Pythonic way to flatten nested dictionarys
Here's my attempt to write a function that flattens a nested dictionary structure in Python 3.6
This came about because I had a nested dictionary structure of data I wanted to visualize in the ...
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Recursive conversion from ExpandoObject to Dictionary<string, object> #2
Because my original question was lacking many details, I have been advised to ask a new question.
I will repeat the important parts of the original question and add examples etc to hopefully make it ...
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Finding added keys, removed keys, and unchanged keys in ordereddict
I'm comparing two OrderedDict objects and I need to find added keys, removed keys, and keys that are present in both (the intersection). Sets are designed for ...
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Recursive conversion from ExpandoObject to Dictionary<string, object>
For my blazor library which is a modification of this awesome library I have to convert an ExpandoObject into a ...
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C simple hashcons data structure
I wrote this hashcons data structure in C and it works correctly. It uses larger twin primes as the capacity and double hashing (open addressing). Page 614 of "Data Structures and Other Objects ...
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Van Emde Boas tree -based map in Java [duplicate]
(Follow-up question: Improved Van Emde Boas tree based map in Java)
For the experimental part of my MSc thesis I was working on van Emde Boas tree, and I have this:
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Function that shortens a String based on a term/abbreviation mapping
I have a function that takes a description as a String and returns a shortened version of the description.
The shortening is done by checking if a word matches the ...
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sorting a map by converting it to vector
I have a map that I want to print out sorted by value, I convert it to vector and sort the vector. Is this code correct?
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Search in a big dictionary Python
I have a big Python dictionary with more then 150,000 keys every key has list value. This dictionary contains infinitive words as key and all grammatical forms of these words as values:
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Tracking the number of string elements using std::unordered_map
I'm looking for the most simple and efficient way to track the number of string elements in a container.
Previously, I used std::vector but I tried changing the ...
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Refactor deeply nested if-else
I found a code on my computer that i wrote a while ago. It is based on an exercise from O'Reilly book Programming the Semantic Web. There is a class, that stores RDF triples, that is data in the form ...
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Generic implementation of a hashtable with double-linked list
I implemented a hashtable that handles collisions by chaining entries using a double linked list.
The idea is that it can store/lookup any kind of generic data structure, while maintaining an API that ...
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A 'flexible' VBA approach to lookups using arrays, scripting dictionary and user input
In my previous post Optimise compare and match method using scripting.dictionary in VBA I wanted to address optimising the scripting.dictionary approach I was using and I feel I have achieved that (...
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A program to display, update and save a dictionary as .csv
I'm now looking for feedback on v2.0 of this program instead.
I'd like some feedback about my code. What bad habits do I have? What advice could help me write more Pythonic?
I'm trying to write a ...
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Data Persistence
I was wondering if I could get some feedback on the library I created to persist data online.
JitterPushDemo.java
...
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Morse code string - follow-up 2
This is my second follow-up. Major changes made:
Use a Map instead of an enum for the Morse characters
Added ...
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Most common occurrence of an int in an array
I am prepping for a junior level interview in C#. I am hoping I can get some feedback on how to improve my code to print the most common occurrence of an int in an ...
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DataTable runtime grouping on user defined criteria
I one of my tools I use the user can define grouping for a DataTable. The criteria are known only at run-time. To achieve this I use a ...
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Transliterate between Cyrillic and Latin scripts
I want to get a code review on the following transliteration code. I wrote it because there were some libraries that I have tried and they were specifically failing with the name "Yuliya" ...
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Website Spell Checker in Java
I've implemented a program that spell checks a website.
Here is the idea that I have in mind:
Scan all of the words in a web page into a string (using jsoup)
Filter out all of the HTML markup and ...
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