TheAlgorithms-C-Plus-Plus/data_structures/trie_modern.cpp
Krishna Vedala aaa08b0150
Major rework to improve code quality and add automation checks (#805)
* delete secant method - it is identical to regula falsi

* document + improvize root finding algorithms

* attempt to document gaussian elimination

* added file brief

* commented doxygen-mainpage, added files-list link

* corrected files list link path

* files-list link correction - this time works :)

* document successive approximations

* cleaner equation

* updating DIRECTORY.md

* documented kmp string search

* document brute force string search

* document rabin-karp string search

* fixed mainpage readme

* doxygen v1.8.18 will suppress out the #minipage in the markdown

* cpplint correction for header guard style

* github action to auto format source code per cpplint standard

* updated setting to add 1 space before `private` and `public` keywords

* auto rename files and auto format code

* added missing "run" for step

* corrected asignmemt operation

* fixed trim and assign syntax

* added git move for renaming bad filenames

* added missing pipe for trim

* added missing space

* use old and new fnames

* store old fname using echo

* move files only if there is a change in filename

* put old filenames in quotes

* use double quote for old filename

* escape double quotes

* remove old_fname

* try escape characters and echo"

* add file-type to find

* cleanup echo

* ensure all trim variables are also in quotes

* try escape -quote again

* remove second escpe quote

* use single quote for first check

* use carets instead of quotes

* put variables in brackets

* remove -e from echo

* add debug echos

* try print0 flag

* find command with while instead of for-loop

* find command using IFS instead

* 🎉 IFS fix worked - escaped quotes for git mv

* protetc each word in git mv ..

* filename exists in lower cases - renamed

* 🎉 git push enabled

* updating DIRECTORY.md

* git pull & then push

* formatting filenames d7af6fdc8c

* formatting source-code for d7af6fdc8c

* remove allman break before braces

* updating DIRECTORY.md

* added missing comma lost in previous commit

* orchestrate all workflows

* fix yml indentation

* force push format changes, add title to DIRECTORY.md

* pull before proceeding

* reorganize pull commands

* use master branches for actions

* rename .cc files to .cpp

* added class destructor to clean up dynamic memory allocation

* rename to awesome workflow

* commented whole repo cpplint - added modified files lint check

* removed need for cpplint

* attempt to use actions/checkout@master

* temporary: no dependency on cpplint

* formatting filenames 153fb7b8a5

* formatting source-code for 153fb7b8a5

* updating DIRECTORY.md

* fix diff filename

* added comments to the code

* added test case

* formatting source-code for a850308fba

* updating DIRECTORY.md

* added machine learning folder

* added adaline algorithm

* updating DIRECTORY.md

* fixed issue [LWG2192](https://cplusplus.github.io/LWG/issue2192) for std::abs on MacOS

* add cmath for same bug: [LWG2192](https://cplusplus.github.io/LWG/issue2192) for std::abs on MacOS

* formatting source-code for f8925e4822

* use STL's inner_product

* formatting source-code for f94a330594

* added range comments

* define activation function

* use equal initial weights

* change test2 function to predict

* activation function not friend

* previous commit correction

* added option for predict function to return value before applying activation function as optional argument

* added test case to classify points lying within a sphere

* improve documentation for adaline

* formatting source-code for 15ec4c3aba

* added cmake to geometry folder

* added algorithm include for std::max

* add namespace - machine_learning

* add namespace - statistics

* add namespace - sorting

* added sorting algos to namespace sorting

* added namespace string_search

* formatting source-code for fd69530515

* added documentation to string_search namespace

* feat: Add BFS and DFS algorithms to check for cycle in a directed graph

* Remove const references for input of simple types

Reason: overhead on access

* fix bad code

sorry for force push

* Use pointer instead of the non-const reference

because apparently google says so.

* Remove a useless and possibly bad Graph constuctor overload

* Explicitely specify type of vector during graph instantiation

* updating DIRECTORY.md

* find openMP before adding subdirectories

* added kohonen self organizing map

* updating DIRECTORY.md

* remove older files and folders from gh-pages before adding new files

* remove chronos library due to inacceptability by cpplint

* use c++ specific static_cast instead

* initialize radom number generator

* updated image links with those from CPP repository

* rename computer.... folder to numerical methods

* added durand kerner method for root computation for arbitrarily large polynomials

* fixed additional comma

* fix cpplint errors

* updating DIRECTORY.md

* convert to function module

* update documentation

* move openmp to main loop

* added two test cases

* use INT16_MAX

* remove return statement from omp-for loop and use "break"

* run tests when no input is provided and skip tests when input polynomial is provided

* while loop cannot have break - replaced with continue and check is present in the main while condition

* (1) break while loop (2) skip runs on break_loop instead of hard-break

* add documentation images

* use long double for errors and tolerance checks

* make iterator variable i local to threads

* add critical secions to omp threads

* bugfix: move file writing outside of the parallel loop
othersie, there is no gurantee of the order of roots written to file

* rename folder to data_structures

* updating DIRECTORY.md

* fix ambiguous symbol `size`

* add data_structures to cmake

* docs: enable tree view, add timestamp in footer, try clang assistaed parsing

* doxygen - open links in external window

* remove invalid parameter from function docs

* use HTML5 img tag to resize images

* move file to proper folder

* fix documentations and cpplint

* formatting source-code for aacaf9828c

* updating DIRECTORY.md

* cpplint: add braces for multiple statement if

* add explicit link to badges

* remove  duplicate line

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* remove namespace indentation

* remove file associations in settings

* add author name

* enable cmake in subfolders of data_structures

* create and link object file

* cpp lint fixes and instantiate template classes

* cpp lint fixes and instantiate template classes

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* cpplint - ignore `build/include`

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* disable redundant gcc compilation in cpplint workflow

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* template header files contain function codes as well and removed redundant subfolders

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* updating DIRECTORY.md

* remove semicolons after functions in a class

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* cpplint header guard style

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* remove semilon

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* added LU decomposition algorithm

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* added QR decomposition algorithm

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* use QR decomposition to find eigen values

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* updating DIRECTORY.md

* use std::rand for thread safety

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* move srand to main()

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* cpplint braces correction

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* updated eigen value documentation

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* fix matrix shift doc

Signed-off-by: Krishna Vedala <7001608+kvedala@users.noreply.github.com>

* rename CONTRIBUTION.md to CONTRIBUTING.md #836

* remove 'sort alphabetical order' check

* added documentation check

* remove extra paranthesis

* added gitpod

* added gitpod link from README

* attempt to add vscode gitpod extensions

* update gitpod extensions

* add gitpod extensions cmake-tools and git-graph

* remove gitpod init and add commands

* use init to one time install doxygen, graphviz, cpplint

* use gitpod dockerfile

* add ninja build system to docker

* remove configure task

* add github prebuild specs to gitpod

* disable gitpod addcommit

* update documentation for kohonen_som

* added ode solve using forward euler method

* added mid-point euler ode solver

* fixed itegration step equation

* added semi-implicit euler ODE solver

* updating DIRECTORY.md

* fix cpplint issues - lines 117 and 124

* added documentation to ode group

* corrected semi-implicit euler function

* updated docs and test cases better structure

* replace `free` with `delete` operator

* formatting source-code for f55ab50cf2

* updating DIRECTORY.md

* main function must return

* added machine learning group

* added kohonen som topology algorithm

* fix graph image path

* updating DIRECTORY.md

* fix braces

* use snprintf instead of sprintf

* use static_cast

* hardcode character buffer size

* fix machine learning groups in documentation

* fix missing namespace function

* replace kvedala fork references to TheAlgorithms

* fix bug in counting_sort

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: Anmol3299 <mittalanmol22@gmail.com>
2020-06-19 21:34:56 +05:30

169 lines
5.5 KiB
C++

/**
* @file
*
* Copyright 2020 @author Anmol3299
* \brief A basic implementation of trie class to store only lower-case strings.
*/
#include <iostream> // for io operations
#include <memory> // for std::shared_ptr<>
#include <string> // for std::string class
/**
* A basic implementation of trie class to store only lower-case strings.
* You can extend the implementation to all the ASCII characters by changing the
* value of @ ALPHABETS to 128.
*/
class Trie {
private:
static constexpr size_t ALPHABETS = 26;
/**
* Structure of trie node.
* This struct doesn't need a constructor as we are initializing using
* intializer list which is more efficient than if we had done so with
* constructor.
*/
struct TrieNode {
// An array of pointers of size 26 which tells if a character of word is
// present or not.
std::shared_ptr<TrieNode> character[ALPHABETS]{nullptr};
bool isEndOfWord{false};
};
/**
* Function to check if a node has some children which can form words.
* @param node whose character array of pointers need to be checked for
* children.
* @return `true` if a child is found
* @return `false` if a child is not found
*/
inline static bool hasChildren(std::shared_ptr<TrieNode> node) {
for (size_t i = 0; i < ALPHABETS; i++) {
if (node->character[i]) {
return true;
}
}
return false;
}
/**
* A recursive helper function to remove a word from the trie. First, it
* recursively traverses to the location of last character of word in the
* trie. However, if the word is not found, the function returns a runtime
* error. Upon successfully reaching the last character of word in trie, if
* sets the isEndOfWord to false and deletes the node if and only if it has
* no children, else it returns the current node.
* @param word is the string which needs to be removed from trie.
* @param curr is the current node we are at.
* @param index is the index of the @word we are at.
* @return if current node has childern, it returns @ curr, else it returns
* nullptr.
* @throw a runtime error in case @ word is not found in the trie.
*/
std::shared_ptr<TrieNode> removeWordHelper(const std::string& word,
std::shared_ptr<TrieNode> curr,
size_t index) {
if (word.size() == index) {
if (curr->isEndOfWord) {
curr->isEndOfWord = false;
}
if (hasChildren(curr)) {
return curr;
}
return nullptr;
}
size_t idx = word[index] - 'a';
// Throw a runtime error in case the user enters a word which is not
// present in the trie.
if (!curr->character[idx]) {
throw std::runtime_error(std::move(std::string("Word not found.")));
}
curr->character[idx] =
removeWordHelper(word, curr->character[idx], index + 1);
// This if condition checks if the node has some childern.
// The 1st if check, i.e. (curr->character[idx]) is checked specifically
// because if the older string is a prefix of some other string, then,
// there would be no need to check all 26 characters. Example- str1 =
// abbey, str2 = abbex and we want to delete string "abbey", then in
// this case, there would be no need to check all characters for the
// chars a,b,b.
if (curr->character[idx] || hasChildren(curr)) {
return curr;
}
return nullptr;
}
public:
/// constructor to initialise the root of the trie.
Trie() : m_root(std::make_shared<TrieNode>()) {}
/**
* Insert a word into the trie.
* @param word which needs to be inserted into the string.
*/
void insert(const std::string& word) {
auto curr = m_root;
for (char ch : word) {
size_t index = ch - 'a';
// if a node for current word is not already present in trie, create
// a new node for it.
if (!curr->character[index]) {
curr->character[index] = std::make_shared<TrieNode>();
}
curr = curr->character[index];
}
curr->isEndOfWord = true;
}
/**
* Search if a word is present in trie or not.
* @param word which is needed to be searched in the trie.
* @return True if the word is found in trie and isEndOfWord is set to true.
* @return False if word is not found in trie or isEndOfWord is set to
* false.
*/
bool search(const std::string& word) {
auto curr = m_root;
for (char ch : word) {
size_t index = ch - 'a';
// if any node for a character is not found, then return that the
// word cannot be formed.
if (!curr->character[index]) {
return false;
}
curr = curr->character[index];
}
return curr->isEndOfWord;
}
// Function to remove the word which calls the helper function.
void removeWord(const std::string& word) {
m_root = removeWordHelper(word, m_root, 0);
}
private:
// data member to store the root of the trie.
std::shared_ptr<TrieNode> m_root;
};
/**
* Main function
*/
int main() {
Trie trie;
trie.insert("hel");
trie.insert("hello");
trie.removeWord("hel");
std::cout << trie.search("hello") << '\n';
return 0;
}