Merge branch 'master' into master

This commit is contained in:
vinayak
2020-05-03 20:17:33 +05:30
committed by GitHub
5 changed files with 479 additions and 377 deletions

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CONTRIBUTING.md Normal file
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# Contributing guidelines
## Before contributing
Welcome to [TheAlgorithms/Javascript](https://github.com/TheAlgorithms/Javascript)! Before sending your pull requests, make sure that you **read the whole guidelines**. If you have any doubt on the contributing guide, please feel free to [state it clearly in an issue](https://github.com/TheAlgorithms/Javascript/issues/new)
## Contributing
### Contributor
We are very happy that you consider implementing algorithms and data structure for others! This repository is referenced and used by learners from around the globe. Being one of our contributors, you agree and confirm that:
- You did your work - plagiarism is not allowed.
- Any plagiarized work will not be merged.
- Your work will be distributed under [GNU License](License) once your pull request is merged
- You submitted work fulfils or mostly fulfils our styles and standards
**New implementation** is welcome! For example, new solutions to a problem, different representations of a graph data structure or algorithm designs with different complexity.
**Improving comments** and **writing proper tests** are also highly welcome.
### Contribution
We appreciate any contribution, from fixing grammar mistakes to implementing complex algorithms. Please read this section if you are contributing your work.
If you submit a pull request that resolves an open issue, please help us to keep our issue list small by adding `fixes: #{$ISSUE_NO}` to your commit message. GitHub will use this tag to auto close the issue if your PR is merged.
#### What is an Algorithm?
An Algorithm is one or more functions (or classes) that:
* take one or more inputs,
* perform some internal calculations or data manipulations,
* return one or more outputs,
* have minimal side effects.
Algorithms should be packaged in a way that would make it easy for readers to put them into larger programs.
Algorithms should:
* have intuitive class and function names that make their purpose clear to readers
* use JavaScript naming conventions and intuitive variable names to ease comprehension
* be flexible to take different input values
* raise JavaScript exceptions (RangeError, etc.) on erroneous input values
Algorithms in this repo should not be how-to examples for existing JavaScript packages. Instead, they should perform internal calculations or manipulations to convert input values into different output values. Those calculations or manipulations can use data types, classes, or functions of existing JavaScript packages but each algorithm in this repo should add unique value.
#### Coding Style
To maximize the readability and correctness of our code, we require that new submissions follow [JavaScript Standard Style](https://standardjs.com/)
- Command to install JavaScript Standard Style
```
$ npm install standard --save-dev
```
- Usage
```
$ standard MyFile.js // if that fails, try: npx standard MyFile.js
```
- Use camelCase for with leading character lowercase for identifier names (variables and functions)
- Names start with a letter
- follow code indentation
- Always use 2 spaces for indentation of code blocks
```
function sumOfArray (arrayOfNumbers) {
let sum = 0
for (let i = 0; i < arrayOfNumbers.length; i++) {
sum += arrayOfNumbers[i]
}
return (sum)
}
```
- Avoid using global variables and avoid '=='
- Please use 'let' over 'var'
- We strongly recommend the use of ECMAScript 6
- Avoid importing external libraries for basic algorithms. Only use those libraries for complicated algorithms.
- Most importantly,
- **Be consistent in the use of these guidelines when submitting.**
- Happy coding!
Writer [@itsvinayak](https://github.com/itsvinayak), May 2020.

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@ -1,195 +1,198 @@
// Hamza chabchoub contribution for a university project
function doubleLinkedList () {
const Node = function (element) {
this.element = element
this.next = null
this.prev = null
}
let length = 0
let head = null
let tail = null
// Add new element
this.append = function (element) {
const node = new Node(element)
if (!head) {
head = node
tail = node
} else {
node.prev = tail
tail.next = node
tail = node
//Hamza chabchoub contribution for a university project
function doubleLinkedList() {
let Node = function(element) {
this.element = element;
this.next = null;
this.prev = null;
}
length++
}
// Add element
this.insert = function (position, element) {
// Check of out-of-bound values
if (position >= 0 && position <= length) {
const node = new Node(element)
let current = head
let previous
let index = 0
if (position === 0) {
if (!head) {
head = node
tail = node
} else {
node.next = current
current.prev = node
head = node
let length = 0;
let head = null;
let tail = null;
//Add new element
this.append = function(element) {
let node = new Node(element);
if(!head){
head = node;
tail = node;
}else{
node.prev = tail;
tail.next = node;
tail = node;
}
length++;
}
//Add element
this.insert = function(position, element) {
//Check of out-of-bound values
if(position >= 0 && position <= length){
let node = new Node(element),
current = head,
previous,
index = 0;
if(position === 0){
if(!head){
head = node;
tail = node;
}else{
node.next = current;
current.prev = node;
head = node;
}
}else if(position === length){
current = tail;
current.next = node;
node.prev = current;
tail = node;
}else{
while(index++ < position){
previous = current;
current = current.next;
}
node.next = current;
previous.next = node;
//New
current.prev = node;
node.prev = previous;
}
} else if (position === length) {
current = tail
current.next = node
node.prev = current
tail = node
} else {
while (index++ < position) {
previous = current
current = current.next
}
node.next = current
previous.next = node
// New
current.prev = node
node.prev = previous
length++;
return true;
}else{
return false;
}
length++
return true
} else {
return false
}
}
// Remove element at any position
this.removeAt = function (position) {
// look for out-of-bounds value
if (position > -1 && position < length) {
let current = head; let previous; let index = 0
// Removing first item
if (position === 0) {
head = current.next
// if there is only one item, update tail //NEW
if (length === 1) {
tail = null
} else {
head.prev = null
//Remove element at any position
this.removeAt = function(position){
//look for out-of-bounds value
if(position > -1 && position < length){
let current = head, previous, index = 0;
//Removing first item
if(position === 0){
head = current.next;
//if there is only one item, update tail //NEW
if(length === 1){
tail = null;
}else{
head.prev = null;
}
}else if(position === length - 1){
current = tail;
tail = current.prev;
tail.next = null;
}else{
while(index++ < position){
previous = current;
current = current.next;
}
//link previous with current's next - skip it
previous.next = current.next;
current.next.prev = previous;
}
} else if (position === length - 1) {
current = tail
tail = current.prev
tail.next = null
} else {
while (index++ < position) {
previous = current
current = current.next
length--;
return current.element;
}else{
return null;
}
}
//Get the indexOf item
this.indexOf = function(elm){
let current = head,
index = -1;
//If element found then return its position
while(current){
if(elm === current.element){
return ++index;
}
// link previous with current's next - skip it
previous.next = current.next
current.next.prev = previous
index++;
current = current.next;
}
//Else return -1
return -1;
};
//Find the item in the list
this.isPresent = (elm) => {
return this.indexOf(elm) !== -1;
};
//Delete an item from the list
this.delete = (elm) => {
return this.removeAt(this.indexOf(elm));
};
//Delete first item from the list
this.deleteHead = function(){
this.removeAt(0);
}
//Delete last item from the list
this.deleteTail = function(){
this.removeAt(length-1);
}
//Print item of the string
this.toString = function(){
let current = head,
string = '';
while(current){
string += current.element + (current.next ? '\n' : '');
current = current.next;
}
length--
return current.element
} else {
return null
}
}
// Get the indexOf item
this.indexOf = function (elm) {
let current = head
let index = -1
// If element found then return its position
while (current) {
if (elm === current.element) {
return ++index
return string;
};
//Convert list to array
this.toArray = function(){
let arr = [],
current = head;
while(current){
arr.push(current.element);
current = current.next;
}
index++
current = current.next
return arr;
};
//Check if list is empty
this.isEmpty = function(){
return length === 0;
};
//Get the size of the list
this.size = function(){
return length;
}
// Else return -1
return -1
}
// Find the item in the list
this.isPresent = (elm) => {
return this.indexOf(elm) !== -1
}
// Delete an item from the list
this.delete = (elm) => {
return this.removeAt(this.indexOf(elm))
}
// Delete first item from the list
this.deleteHead = function () {
this.removeAt(0)
}
// Delete last item from the list
this.deleteTail = function () {
this.removeAt(length - 1)
}
// Print item of the string
this.toString = function () {
let current = head
let string = ''
while (current) {
string += current.element + (current.next ? '\n' : '')
current = current.next
//Get the head
this.getHead = function() {
return head;
}
return string
}
// Convert list to array
this.toArray = function () {
const arr = []
let current = head
while (current) {
arr.push(current.element)
current = current.next
//Get the tail
this.getTail = function() {
return tail;
}
}
return arr
}
// Check if list is empty
this.isEmpty = function () {
return length === 0
}
// Get the size of the list
this.size = function () {
return length
}
// Get the head
this.getHead = function () {
return head
}
// Get the tail
this.getTail = function () {
return tail
}
}

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@ -1,58 +1,60 @@
function TopologicalSorter () {
var graph = {}
var isVisitedNode
var finishTimeCount
var finishingTimeList
var nextNode
this.addOrder = function (nodeA, nodeB) {
nodeA = String(nodeA)
nodeB = String(nodeB)
graph[nodeA] = graph[nodeA] || []
graph[nodeA].push(nodeB)
}
function TopologicalSorter() {
var graph = {},
isVisitedNode,
finishTimeCount,
finishingTimeList,
nextNode;
this.sortAndGetOrderedItems = function () {
isVisitedNode = Object.create(null)
finishTimeCount = 0
finishingTimeList = []
this.addOrder = function (nodeA, nodeB) {
nodeA = String(nodeA);
nodeB = String(nodeB);
graph[nodeA] = graph[nodeA] || [];
graph[nodeA].push(nodeB);
}
this.sortAndGetOrderedItems = function () {
isVisitedNode = Object.create(null);
finishTimeCount = 0;
finishingTimeList = [];
for (var node in graph) {
if (graph.hasOwnProperty(node) && !isVisitedNode[node]) {
dfsTraverse(node)
}
for (var node in graph) {
if (graph.hasOwnProperty(node) && !isVisitedNode[node]) {
dfsTraverse(node);
}
}
finishingTimeList.sort(function (item1, item2) {
return item1.finishTime > item2.finishTime ? -1 : 1;
});
return finishingTimeList.map(function (value) { return value.node })
}
finishingTimeList.sort(function (item1, item2) {
return item1.finishTime > item2.finishTime ? -1 : 1
})
function dfsTraverse(node) {
isVisitedNode[node] = true;
if (graph[node]) {
for (var i = 0; i < graph[node].length; i++) {
nextNode = graph[node][i];
if (isVisitedNode[nextNode]) continue;
dfsTraverse(nextNode);
}
}
return finishingTimeList.map(function (value) { return value.node })
}
function dfsTraverse (node) {
isVisitedNode[node] = true
if (graph[node]) {
for (var i = 0; i < graph[node].length; i++) {
nextNode = graph[node][i]
if (isVisitedNode[nextNode]) continue
dfsTraverse(nextNode)
}
finishingTimeList.push({
node: node,
finishTime: ++finishTimeCount
});
}
finishingTimeList.push({
node: node,
finishTime: ++finishTimeCount
})
}
}
/* TEST */
var topoSorter = new TopologicalSorter()
topoSorter.addOrder(5, 2)
topoSorter.addOrder(5, 0)
topoSorter.addOrder(4, 0)
topoSorter.addOrder(4, 1)
topoSorter.addOrder(2, 3)
topoSorter.addOrder(3, 1)
console.log(topoSorter.sortAndGetOrderedItems())
var topoSorter = new TopologicalSorter();
topoSorter.addOrder(5, 2);
topoSorter.addOrder(5, 0);
topoSorter.addOrder(4, 0);
topoSorter.addOrder(4, 1);
topoSorter.addOrder(2, 3);
topoSorter.addOrder(3, 1);
console.log(topoSorter.sortAndGetOrderedItems());

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@ -1,66 +1,71 @@
// starting at s
function solve (graph, s) {
var solutions = {}
solutions[s] = []
solutions[s].dist = 0
function solve(graph, s) {
var solutions = {};
solutions[s] = [];
solutions[s].dist = 0;
while(true) {
var p = null;
var neighbor = null;
var dist = Infinity;
for(var n in solutions) {
if(!solutions[n])
continue
var ndist = solutions[n].dist;
var adj = graph[n];
for(var a in adj) {
while (true) {
var p = null
var neighbor = null
var dist = Infinity
for (var n in solutions) {
if (!solutions[n]) { continue }
var ndist = solutions[n].dist
var adj = graph[n]
for (var a in adj) {
if (solutions[a]) { continue }
var d = adj[a] + ndist
if (d < dist) {
p = solutions[n]
neighbor = a
dist = d
if(solutions[a])
continue;
var d = adj[a] + ndist;
if(d < dist) {
p = solutions[n];
neighbor = a;
dist = d;
}
}
}
// no more solutions
if (dist === Infinity) {
break
//no more solutions
if(dist === Infinity) {
break;
}
// extend parent's solution path
solutions[neighbor] = p.concat(neighbor)
// extend parent's cost
solutions[neighbor].dist = dist
//extend parent's solution path
solutions[neighbor] = p.concat(neighbor);
//extend parent's cost
solutions[neighbor].dist = dist;
}
return solutions
return solutions;
}
// create graph
var graph = {}
//create graph
var graph = {};
var layout = {
R: ['2'],
2: ['3', '4'],
3: ['4', '6', '13'],
4: ['5', '8'],
5: ['7', '11'],
6: ['13', '15'],
7: ['10'],
8: ['11', '13'],
9: ['14'],
10: [],
11: ['12'],
12: [],
13: ['14'],
14: [],
15: []
'R': ['2'],
'2': ['3','4'],
'3': ['4','6','13'],
'4': ['5','8'],
'5': ['7','11'],
'6': ['13','15'],
'7': ['10'],
'8': ['11','13'],
'9': ['14'],
'10': [],
'11': ['12'],
'12': [],
'13': ['14'],
'14': [],
'15': []
}
// convert uni-directional to bi-directional graph
//convert uni-directional to bi-directional graph
// var graph = {
// a: {e:1, b:1, g:3},
// b: {a:1, c:1},
@ -72,25 +77,27 @@ var layout = {
// h: {f:1}
// };
for (var id in layout) {
if (!graph[id]) { graph[id] = {} }
layout[id].forEach(function (aid) {
graph[id][aid] = 1
if (!graph[aid]) { graph[aid] = {} }
graph[aid][id] = 1
})
for(var id in layout) {
if(!graph[id])
graph[id] = {};
layout[id].forEach(function(aid) {
graph[id][aid] = 1;
if(!graph[aid])
graph[aid] = {};
graph[aid][id] = 1;
});
}
// choose start node
var start = '10'
// get all solutions
var solutions = solve(graph, start)
//choose start node
var start = '10';
//get all solutions
var solutions = solve(graph, start);
console.log("From '" + start + "' to")
// display solutions
for (var s in solutions) {
if (!solutions[s]) continue
console.log(' -> ' + s + ': [' + solutions[s].join(', ') + '] (dist:' + solutions[s].dist + ')')
console.log("From '"+start+"' to");
//display solutions
for(var s in solutions) {
if(!solutions[s]) continue;
console.log(" -> " + s + ": [" + solutions[s].join(", ") + "] (dist:" + solutions[s].dist + ")");
}
// From '10' to

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@ -1,89 +1,95 @@
// create a graph class
class Graph {
// defining vertex array and
// adjacent list
constructor (noOfVertices) {
this.noOfVertices = noOfVertices
this.AdjList = new Map()
}
// functions to be implemented
// addVertex(v)
// addEdge(v, w)
// printGraph()
// bfs(v)
// dfs(v)
// create a graph class
class Graph {
// defining vertex array and
// adjacent list
constructor(noOfVertices)
{
this.noOfVertices = noOfVertices;
this.AdjList = new Map();
}
// functions to be implemented
// addVertex(v)
// addEdge(v, w)
// printGraph()
// bfs(v)
// dfs(v)
}
// add vertex to the graph
addVertex(v)
{
// initialize the adjacent list with a
// null array
this.AdjList.set(v, [])
// add vertex to the graph
addVertex(v)
{
// initialize the adjacent list with a
// null array
this.AdjList.set(v, []);
}
// add edge to the graph
addEdge(v, w)
{
// get the list for vertex v and put the
// vertex w denoting edge between v and w
this.AdjList.get(v).push(w)
// add edge to the graph
addEdge(v, w)
{
// get the list for vertex v and put the
// vertex w denoting edge between v and w
this.AdjList.get(v).push(w);
// Since graph is undirected,
// add an edge from w to v also
this.AdjList.get(w).push(v);
}
// Since graph is undirected,
// add an edge from w to v also
this.AdjList.get(w).push(v)
// Prints the vertex and adjacency list
printGraph()
{
// get all the vertices
var get_keys = this.AdjList.keys();
// iterate over the vertices
for (var i of get_keys)
{
// great the corresponding adjacency list
// for the vertex
var get_values = this.AdjList.get(i);
var conc = "";
// iterate over the adjacency list
// concatenate the values into a string
for (var j of get_values)
conc += j + " ";
// print the vertex and its adjacency list
console.log(i + " -> " + conc);
}
}
// Prints the vertex and adjacency list
printGraph()
{
// get all the vertices
var get_keys = this.AdjList.keys()
// iterate over the vertices
for (var i of get_keys) {
// great the corresponding adjacency list
// for the vertex
var get_values = this.AdjList.get(i)
var conc = ''
// iterate over the adjacency list
// concatenate the values into a string
for (var j of get_values) { conc += j + ' ' }
// print the vertex and its adjacency list
console.log(i + ' -> ' + conc)
}
}
// Example
var graph = new Graph(6)
var vertices = ['A', 'B', 'C', 'D', 'E', 'F']
var graph = new Graph(6);
var vertices = [ 'A', 'B', 'C', 'D', 'E', 'F' ];
// adding vertices
for (var i = 0; i < vertices.length; i++) {
g.addVertex(vertices[i]);
}
// adding edges
g.addEdge('A', 'B');
g.addEdge('A', 'D');
g.addEdge('A', 'E');
g.addEdge('B', 'C');
g.addEdge('D', 'E');
g.addEdge('E', 'F');
g.addEdge('E', 'C');
g.addEdge('C', 'F');
// prints all vertex and
// its adjacency list
// A -> B D E
// B -> A C
// C -> B E F
// D -> A E
// E -> A D F C
// F -> E C
g.printGraph();
// adding vertices
for (var i = 0; i < vertices.length; i++) {
g.addVertex(vertices[i])
}
// adding edges
g.addEdge('A', 'B')
g.addEdge('A', 'D')
g.addEdge('A', 'E')
g.addEdge('B', 'C')
g.addEdge('D', 'E')
g.addEdge('E', 'F')
g.addEdge('E', 'C')
g.addEdge('C', 'F')
// prints all vertex and
// its adjacency list
// A -> B D E
// B -> A C
// C -> B E F
// D -> A E
// E -> A D F C
// F -> E C
g.printGraph()