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Dutch national flag problem in Javascript

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Dutch national flag problem and solution in Javascript Problem statement:   The Dutch national flag (DNF) problem is one of the most popular programming problems proposed by Edsger Dijkstra. The flag of the Netherlands consists of three colors: white, red, and blue. The task is to randomly arrange balls of white, red, and blue such that balls of the same color are placed together. Now, let's consider an array with 3 distinct values say 0, 1 and 2. We won't be using any sort method and we need to sort this array in 0(n). Input Array :  let   arr  = [ 0 ,  2 ,  1 ,  0 ,  1 ,  2 ,  0 ,  2 ]; Expected Output: [ 0, 0, 0, 1, 1, 2, 2, 2 ] Solution Approach : When we see expected output, we can clearly see that sorted array is divided into 3 sections having values 0 , 1 and 2. So, let's divide the array in 3 sections: a) from 0th index to left boundary b) from left boundary to right boundary c) from right boundary to last index. Now we...
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Javascript Codewars Problem: "Highest Rank Number in an Array"

  Codewars   Problem and solution in Javascript Objective:   In this challenge, we will solve the “ Highest Rank Number in an Array ”   Codewars  Kata  using  javascript .   Problem statement:   Complete the method which returns the number which is most frequent in the given input array. If there is a tie for most frequent number, return the largest number among them.   Examples:   Input  :  [12, 10, 8, 12, 7, 6, 4, 10, 12] Output  :  12 Input  :  [12, 10, 8, 12, 7, 6, 4, 10, 12, 10] Output :   12 Input  : [12, 10, 8, 8, 3, 3, 3, 3, 2, 4, 10, 12, 10] Output  :  3 Solution Approach :  we will create a hash-map/object from the given array and store the array elements as key of object and number of element's occurrence as value of that key in object.  For understanding hash-map, refer the blog  post . Once done with the object, we will traverse through the objec...
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Javascript Codewars Problem: "Isograms"

   Codewars   Problem and solution in Javascript     Objective:   In this challenge, we will solve the “ Isograms ”   Codewars   puzzle using  javascript .   Problem statement:   An isogram is a word that has no repeating letters, consecutive or non-consecutive. Implement a function that determines whether a string that contains only letters is an isogram. Assume the empty string is an isogram. Ignore letter case. It must return the display text as shown in the examples:   Examples:   Input  :  Dermatoglyphics Output  :  true Input  : aba  Output :   false Input  : moOse Output  :  false // -- ignore letter case Input  :  isogram Output  :  true Solution  Hint :  we will create a character map from the given string and check if any character repeats or not and return true or false   accordingly. Note: Remember to convert string to l...
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Javascript Codewars Problem: "Who likes it?"

  Codewars   Problem and solution in Javascript     Objective:   In this challenge, we will solve the “ Who likes it? ”  Codewars   puzzle using  javascript .   Problem statement:   You probably know the "like" system from Facebook and other pages. People can "like" blog posts, pictures or other items. We want to create the text that should be displayed next to such an item. Implement a function likes :: [String] -> String, which must take in input array, containing the names of people who like an item. It must return the display text as shown in the examples:   Examples:   Input  :  [] Output  :  no one likes this Input  : ['Peter']   Output :   Peter likes this Input  : ['Jacob', 'Alex']  Output  :  Jacob and Alex like this Input  :  ['Max', 'John', 'Mark'] Output  :  Max, John and Mark like this Input  :  ['Alex', 'Jacob', 'Mark...
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