How to usemap() method in Javascript
In This approach we are using the map() method to count the occurrences of elements in an array, creating a frequency map. It then converts this map into an array of [element, frequency] pairs, sorts them by frequency in descending order, and finally, extracts the top k elements, providing an efficient solution for finding k most occurring elements.
Syntax:
map((element) => { /* … */ })
Example: Below is the implementation of the above approach.
Javascript
function frequentElements(arr, k) { const frequencyMap = new Map(); // Count the occurrences of // each element in the array for (let i = 0; i < arr.length; i++) { const num = arr[i]; frequencyMap.has(num) ? frequencyMap. set(num, frequencyMap.get(num) + 1) : frequencyMap.set(num, 1); } // Sort the entries in the frequency // map by frequency in descending order const sortedEntries = [...frequencyMap.entries()] .sort((a, b) => b[1] - a[1]); const result = []; // Extract the first k elements // from the sorted entries for (let i = 0; i < k && i < sortedEntries.length; i++) { result.push(sortedEntries[i][0]); } return result; } const arr = [3, 1, 4, 4, 5, 2, 6, 1]; const k = 2; const kMostFrequent = frequentElements(arr, k); console.log(...kMostFrequent); |
Output
1 4
JavaScript Program to Find k Most Occurrences in the Given Array
K most occurrences in an array refer to finding the K unique elements that appear the most frequently within the given array, where K is a specified integer. These are the elements with the highest frequencies in the array.
Example:
Input: arr[] = {3, 1, 4, 4, 5, 2, 6, 1}, K = 2
Output: 4 1
Explanation:
Frequency of 4 = 2, Frequency of 1 = 2
These two have the maximum frequency and 4 is larger than 1.
refer
Input: arr[] = {7, 10, 11, 5, 2, 5, 5, 7, 11, 8, 9}, K = 4
Output: 5 11 7 10
Explanation:
Frequency of 5 = 3, Frequency of 11 = 2, Frequency of 7 = 2, Frequency of 10 = 1
These four have the maximum frequency and 5 is largest among rest.
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