Closing Time Coding Challenge

closingTime.js

/*
 * Complete the 'closingTime' function below.
 *
 * The function is expected to return an INTEGER.
 * The function accepts following parameters:
 *  1. INTEGER_ARRAY queue
 *  2. DOUBLE admission
 *  3. DOUBLE runningCost
 */

function closingTime(queue, admission, runningCost) {
    let runningProfit = 0;
    let runningOverflow = 0;
    let maximumProfit = {
        amount: 0,
        shift: 0,
    };
    for (let i = 0; i < queue.length; i++) {
        runningProfit -= runningCost;
        const shiftOverflow = queue[i] > 4 ? queue[i] - 4 : 0;
        if (shiftOverflow) {
            runningOverflow += shiftOverflow;
        }
        let shiftBoardings = Math.min(queue[i], 4);
        if (shiftBoardings < 4 && runningOverflow > 0) {
            const shiftOpenings = 4 - shiftBoardings;
            if (runningOverflow >= shiftOpenings) {
                shiftBoardings += shiftOpenings;
                runningOverflow -= shiftOpenings;
            } else {
                shiftBoardings += runningOverflow;
                runningOverflow = 0;
            }
        }
        const shiftRevenue = shiftBoardings * admission;
        runningProfit += shiftRevenue;
        if (runningProfit > maximumProfit.amount) {
            maximumProfit.amount = runningProfit;
            maximumProfit.shift = i;
        }
    }
    if (maximumProfit.amount <= 0) return -1;
    return maximumProfit.shift;
}