FraudulentActivityNotifications.js

'use strict';

const fs = require('fs');

process.stdin.resume();
process.stdin.setEncoding('utf-8');

let inputString = '';
let currentLine = 0;

process.stdin.on('data', inputStdin => {
    inputString += inputStdin;
});

process.stdin.on('end', _ => {
    inputString = inputString.replace(/\s*$/, '')
        .split('\n')
        .map(str => str.replace(/\s*$/, ''));

    main();
});

function readLine() {
    return inputString[currentLine++];
}

// Complete the activityNotifications function below.
function activityNotifications(expenditure, d) {
     // Number of notifications
    let n = 0

    // Set midpoints for median calculation
    let [ i1, i2 ] = [ Math.floor((d-1)/2), Math.ceil((d-1)/2) ]
    let m1, m2, m

    // Initialize count sorted subarray
    let cs = new Array(201).fill(0)
    for (let i = d-1; i >= 0; i--) cs[expenditure[i]]++

    // Iterate through expenditures
    for (let i = d, l = expenditure.length; i < l; i++) {

        // Find median
        for (let j = 0, k = 0; k <= i1; k += cs[j], j++) m1 = j
        for (let j = 0, k = 0; k <= i2; k += cs[j], j++) m2 = j
        let m = (m1 + m2) / 2

        // Check if notification is given
        if (expenditure[i] >= m * 2) n++

        // Replace subarray elements
        cs[expenditure[i-d]]--
        cs[expenditure[i]]++
    }

    return n


}

function main() {
    const ws = fs.createWriteStream(process.env.OUTPUT_PATH);

    const nd = readLine().split(' ');

    const n = parseInt(nd[0], 10);

    const d = parseInt(nd[1], 10);

    const expenditure = readLine().split(' ').map(expenditureTemp => parseInt(expenditureTemp, 10));

    let result = activityNotifications(expenditure, d);

    ws.write(result + "\n");

    ws.end();
}