diff --git a/guide/english/certifications/coding-interview-prep/data-structures/create-a-queue-class/index.md b/guide/english/certifications/coding-interview-prep/data-structures/create-a-queue-class/index.md index 9f251bfd0c..703918a9d2 100644 --- a/guide/english/certifications/coding-interview-prep/data-structures/create-a-queue-class/index.md +++ b/guide/english/certifications/coding-interview-prep/data-structures/create-a-queue-class/index.md @@ -3,8 +3,78 @@ title: Create a Queue Class --- ## Create a Queue Class -This is a stub. Help our community expand it. -This quick style guide will help ensure your pull request gets accepted. +### Method: +- A Queue is an abstract Data Structure. +- A Queue folow FIFO/LILO principle. +- In this challenge we nede to implement `enqueue()`, `dequeue()`, `front()`, `size()`, `isEmpty()` methods. + - `enqueue()` - This method adds the element to the queue. + - `dequeue()` - This method removes the first element from the queue. + - `front()` - This method returns the first element in the queue that'd be dequeue'd. + - `size()` - This method returns the size of the queue. + - `isEmpty()` - This method returns if the queue is empty. +- + | DS | Access | Search | Insert | Delete | + | ----- | ------ | ------ | ------ | ------ | + | Queue | n | n | 1 | 1 | + + - ![Queue in action](https://upload.wikimedia.org/wikipedia/commons/thumb/5/52/Data_Queue.svg/405px-Data_Queue.svg.png) - +### Solution: + +#### Basic: +##### Note: +- This solution is not exactly a queue, the shift() method used in the dequeue() method is of complexity `O(n)` and not `O(1)`. However, the advanced solution rectifies this and uses Object(HashTables) instead of Array to implement Queue. +```js +function Queue () { + var collection = []; + this.print = function() { + console.log(collection); + }; + this.enqueue = function(val){ + collection.push(val); + }; + this.dequeue = function(){ + return collection.shift(); + } + this.front = function(){ + return collection[0]; + } + this.size = function(){ + return collection.length; + } + this.isEmpty = function(){ + return collection.length === 0; + } +} +``` +#### Advanced - ES6 class syntax: +```js +class Queue { + constructor(){ + this.collection = {}; + this.start = 0; + this.end = 0; + } + print(){ + console.log(this.collection); + } + enqueue(val){ + this.collection[this.end++] = val; + } + dequeue(){ + return this.collection[this.start++]; + } + front(){ + return this.collection[this.start]; + } + size(){ + return this.end - this.start; + } + isEmpty(){ + return this.size() === 0; + } +} +``` +### References: +- [Wikipedia](https://en.wikipedia.org/wiki/Queue_(abstract_data_type)) diff --git a/guide/english/certifications/coding-interview-prep/project-euler/problem-8-largest-product-in-a-series/index.md b/guide/english/certifications/coding-interview-prep/project-euler/problem-8-largest-product-in-a-series/index.md index d7fa702ae9..148e790b9c 100644 --- a/guide/english/certifications/coding-interview-prep/project-euler/problem-8-largest-product-in-a-series/index.md +++ b/guide/english/certifications/coding-interview-prep/project-euler/problem-8-largest-product-in-a-series/index.md @@ -3,8 +3,41 @@ title: Largest product in a series --- ## Problem 8: Largest product in a series -This is a stub. Help our community expand it. +### Method: -This quick style guide will help ensure your pull request gets accepted. +- In this challenge we need to get the largest product of `n` cosnecutive numbers. +- We can use the sliding window method to solve this problem. +- Steps to follow: + 1. Select the first n consecutive numbers. + 2. Find their product. + 3. Compare it to the maximum product yet. + 4. Move the pointer by 1 element. + 5. Repeat the process. + - This algorithm's big O is **O(n\*m)** where n is the length of the array and m is the number of consecutive elements. +### Solution: +```js +function largestProductinaSeries(n) { + let thousandDigits = [7,3,1,6,7,1,7,6,5,3,1,3,3,0,6,2,4,9,1,9,2,2,5,1,1,9,6,7,4,4,2,6,5,7,4,7,4,2,3,5,5,3,4,9,1,9,4,9,3,4,9,6,9,8,3,5,2,0,3,1,2,7,7,4,5,0,6,3,2,6,2,3,9,5,7,8,3,1,8,0,1,6,9,8,4,8,0,1,8,6,9,4,7,8,8,5,1,8,4,3,8,5,8,6,1,5,6,0,7,8,9,1,1,2,9,4,9,4,9,5,4,5,9,5,0,1,7,3,7,9,5,8,3,3,1,9,5,2,8,5,3,2,0,8,8,0,5,5,1,1,1,2,5,4,0,6,9,8,7,4,7,1,5,8,5,2,3,8,6,3,0,5,0,7,1,5,6,9,3,2,9,0,9,6,3,2,9,5,2,2,7,4,4,3,0,4,3,5,5,7,6,6,8,9,6,6,4,8,9,5,0,4,4,5,2,4,4,5,2,3,1,6,1,7,3,1,8,5,6,4,0,3,0,9,8,7,1,1,1,2,1,7,2,2,3,8,3,1,1,3,6,2,2,2,9,8,9,3,4,2,3,3,8,0,3,0,8,1,3,5,3,3,6,2,7,6,6,1,4,2,8,2,8,0,6,4,4,4,4,8,6,6,4,5,2,3,8,7,4,9,3,0,3,5,8,9,0,7,2,9,6,2,9,0,4,9,1,5,6,0,4,4,0,7,7,2,3,9,0,7,1,3,8,1,0,5,1,5,8,5,9,3,0,7,9,6,0,8,6,6,7,0,1,7,2,4,2,7,1,2,1,8,8,3,9,9,8,7,9,7,9,0,8,7,9,2,2,7,4,9,2,1,9,0,1,6,9,9,7,2,0,8,8,8,0,9,3,7,7,6,6,5,7,2,7,3,3,3,0,0,1,0,5,3,3,6,7,8,8,1,2,2,0,2,3,5,4,2,1,8,0,9,7,5,1,2,5,4,5,4,0,5,9,4,7,5,2,2,4,3,5,2,5,8,4,9,0,7,7,1,1,6,7,0,5,5,6,0,1,3,6,0,4,8,3,9,5,8,6,4,4,6,7,0,6,3,2,4,4,1,5,7,2,2,1,5,5,3,9,7,5,3,6,9,7,8,1,7,9,7,7,8,4,6,1,7,4,0,6,4,9,5,5,1,4,9,2,9,0,8,6,2,5,6,9,3,2,1,9,7,8,4,6,8,6,2,2,4,8,2,8,3,9,7,2,2,4,1,3,7,5,6,5,7,0,5,6,0,5,7,4,9,0,2,6,1,4,0,7,9,7,2,9,6,8,6,5,2,4,1,4,5,3,5,1,0,0,4,7,4,8,2,1,6,6,3,7,0,4,8,4,4,0,3,1,9,9,8,9,0,0,0,8,8,9,5,2,4,3,4,5,0,6,5,8,5,4,1,2,2,7,5,8,8,6,6,6,8,8,1,1,6,4,2,7,1,7,1,4,7,9,9,2,4,4,4,2,9,2,8,2,3,0,8,6,3,4,6,5,6,7,4,8,1,3,9,1,9,1,2,3,1,6,2,8,2,4,5,8,6,1,7,8,6,6,4,5,8,3,5,9,1,2,4,5,6,6,5,2,9,4,7,6,5,4,5,6,8,2,8,4,8,9,1,2,8,8,3,1,4,2,6,0,7,6,9,0,0,4,2,2,4,2,1,9,0,2,2,6,7,1,0,5,5,6,2,6,3,2,1,1,1,1,1,0,9,3,7,0,5,4,4,2,1,7,5,0,6,9,4,1,6,5,8,9,6,0,4,0,8,0,7,1,9,8,4,0,3,8,5,0,9,6,2,4,5,5,4,4,4,3,6,2,9,8,1,2,3,0,9,8,7,8,7,9,9,2,7,2,4,4,2,8,4,9,0,9,1,8,8,8,4,5,8,0,1,5,6,1,6,6,0,9,7,9,1,9,1,3,3,8,7,5,4,9,9,2,0,0,5,2,4,0,6,3,6,8,9,9,1,2,5,6,0,7,1,7,6,0,6,0,5,8,8,6,1,1,6,4,6,7,1,0,9,4,0,5,0,7,7,5,4,1,0,0,2,2,5,6,9,8,3,1,5,5,2,0,0,0,5,5,9,3,5,7,2,9,7,2,5,7,1,6,3,6,2,6,9,5,6,1,8,8,2,6,7,0,4,2,8,2,5,2,4,8,3,6,0,0,8,2,3,2,5,7,5,3,0,4,2,0,7,5,2,9,6,3,4,5,0]; + + let len = n; + let prod = 1, max = 1; + while (len < thousandDigits.length){ + prod = 1; + + //Looping and computing products of n numbers + for (let i = len-n; i < len; i++){ + prod*= thousandDigits[i]; + } + if (prod > max) max = prod; + len++; + } + return max; +} - +console.log(largestProductinaSeries(13)); +``` +- [Run Code](https://repl.it/@ezioda004/Project-Euler-Problem-8-Largest-product-in-a-series) + +### References: + +- [Sliding Window Technique](https://www.geeksforgeeks.org/window-sliding-technique/)