Find Servers That Handled Most Number of Requests LeetCode solution in JavaScript

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var busiestServers = function (k, arrival, load) {
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  let loadMap = {};
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  let pq = new MinPriorityQueue({ compare: (a, b) => a[1] - b[1] });
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  let availableServers = new Set(new Array(k).fill(0).map((_, index) => index));
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  for (let i = 0; i < arrival.length; i++) {
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    // calc end time
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    let end = arrival[i] + load[i];
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    // bring server back
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    while (pq.front()?.[1] <= arrival[i]) {
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      const [server] = pq.dequeue();
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      availableServers.add(server);
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    }
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    let server = i % k;
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    // drop if no available server
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    if (availableServers.size === 0) continue;
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    // find the next avaiable sever
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    while (!availableServers.has(server)) {
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      server++;
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      if (server === k + 1) {
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        server = 0;
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      }
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    }
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    // record the load
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    if (!loadMap[server]) {
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      loadMap[server] = 0;
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    }
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    loadMap[server]++;
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    availableServers.delete(server);
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    pq.enqueue([server, end]);
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  }
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  let res = [];
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  let sorted = Object.entries(loadMap).sort((a, b) => b[1] - a[1]);
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  let max = sorted[0][1];
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  let i = 0;
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  while (sorted[i]?.[1] === max) {
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    res.push(+sorted[i++][0]);
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  }
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  return res;
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};