Question

How to find K most frequent elements in an unsorted array with Node.js

Answer 1

function PrintKMostFrequentNumbers(arr, K) {
    let mp = new Map();
    let size = arr.length;
    
    for (let i = 0; i < size; i++) {
        if (mp.has(arr[i])) {
            mp.set(arr[i], mp.get(arr[i]) + 1)
        } else {
            mp.set(arr[i], 1)
        }
    }
 
    let list = [...mp];
 
    list.sort((e1, e2) => {
        if (e1[1] == e2[1])
            return e2[0] - e1[0];
        else
            return e2[1] - e1[1];
    })
 
    for (let i = 0; i < K; i++)
        console.log(list[i][0]);
}

const arr = [4, 5, 19, 50, 7, 19, 8, 19, 3, 3, 6, 3, 27, 19, 3, 3];
const K = 2;

PrintKMostFrequentNumbers(arr, K);




/*
run:

3
19

*/

 

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Answer 2

function PrintKMostFrequentNumbers(arr, K) {
    let mp = new Map();
    let size = arr.length;
    
    for (let i = 0; i < size; i++) {
        if (mp.has(arr[i])) {
            mp.set(arr[i], mp.get(arr[i]) + 1)
        } else {
            mp.set(arr[i], 1)
        }
    }
    
    mp = new Map([...mp].sort((a, b) => b[1] - a[1]));
    
    for (let i = 0; i < K; i++) {
        console.log(Array.from(mp.keys())[i]);
     }
}

const arr = [4, 5, 19, 50, 7, 19, 8, 19, 3, 3, 6, 3, 27, 19, 3, 3];
const K = 2;

PrintKMostFrequentNumbers(arr, K);




/*
run:

3
19

*/

 

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