Number of Longest Increasing Subsequence LeetCode solution in JavaScript

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var findNumberOfLIS = function (nums) {
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  const { length } = nums;
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  const dpLength = Array(length).fill(1);
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  const dpCount = Array(length).fill(1);
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  for (let right = 0; right < length; right++) {
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    for (let left = 0; left < right; left++) {
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      if (nums[left] >= nums[right]) continue;
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      if (dpLength[left] + 1 === dpLength[right]) {
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        dpCount[right] += dpCount[left];
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      } else if (dpLength[left] + 1 > dpLength[right]) {
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        dpLength[right] = dpLength[left] + 1;
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        dpCount[right] = dpCount[left];
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      }
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    }
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  }
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  const maxLength = Math.max(...dpLength);
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  return dpLength.reduce((result, length, index) => {
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    const count = dpCount[index];
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    return result + (maxLength === length ? count : 0);
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  }, 0);
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};