Capacity To Ship Packages Within D Days LeetCode solution in JavaScript

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/**
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 * @param {number[]} weights
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 * @param {number} days
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 * @return {number}
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 */
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var shipWithinDays = function (weights, days) {
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  // set left as max of weight, set right as sum of weight
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  let left = Math.max(...weights),
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    right = weights.reduce((a, b) => a + b);
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  // max weight cannot exceed the capacity of ship
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  while (left < right) {
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    // set middle weight
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    const m = Math.floor((left + right) / 2);
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    // reset weight if can be load
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    can(m) ? (left = m + 1) : (right = m);
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  }
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  // result
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  return left;
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  // check if load can be
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  function can(v) {
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    let need = 1,
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      current = 0;
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    for (let i of weights) {
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      if (current + i > v) {
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        need++;
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        current = i;
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      } else {
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        current += i;
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      }
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    }
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    return need > days;
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  }
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};