Average Waiting Time LeetCode solution in JavaScript

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/**
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 * @param {number[][]} customers
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 * @return {number}
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 */
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var averageWaitingTime = function (customers) {
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  let n = customers.length;
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  let starts = Array(n).fill(0);
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  // the first customer do not have to wait for the prev customer so his start time == arrival time
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  starts[0] = customers[0][0];
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  let totalWait = customers[0][1];
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  for (let i = 1; i < n; i++) {
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    // The start of the current customer is  the max of (start + time of prev customer) or the arrival time of existing customer
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    starts[i] = Math.max(starts[i - 1] + customers[i - 1][1], customers[i][0]);
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    totalWait += starts[i] - customers[i][0] + customers[i][1];
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  }
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  return totalWait / n;
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};