<p>Given two integer arrays <code>nums1</code> and <code>nums2</code>, return <em>the maximum length of a subarray that appears in <strong>both</strong> arrays</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums1 = [1,2,3,2,1], nums2 = [3,2,1,4,7]
<strong>Output:</strong> 3
<strong>Explanation:</strong> The repeated subarray with maximum length is [3,2,1].
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums1 = [0,0,0,0,0], nums2 = [0,0,0,0,0]
<strong>Output:</strong> 5
<strong>Explanation:</strong> The repeated subarray with maximum length is [0,0,0,0,0].
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= nums1.length, nums2.length &lt;= 1000</code></li>
	<li><code>0 &lt;= nums1[i], nums2[i] &lt;= 100</code></li>
</ul>

from typing import List

class Solution:
    def findLength(self, nums1: List[int], nums2: List[int]) -> int:
        def suffix_array_construction(arr):
            
            suffixes = sorted([(arr[i:], i) for i in range(len(arr))])
            suffix_array = [suffix[1] for suffix in suffixes]
            return suffix_array

        def lcp_array_construction(arr, suffix_array):
            n = len(arr)
            rank = [0] * n
            lcp = [0] * n

           
            for i, suffix_index in enumerate(suffix_array):
                rank[suffix_index] = i

            h = 0
            for i in range(n):
                if rank[i] > 0:
                    j = suffix_array[rank[i] - 1]
                    while i + h < n and j + h < n and arr[i + h] == arr[j + h]:
                        h += 1
                    lcp[rank[i]] = h
                    if h > 0:
                        h -= 1
            return lcp

        def longest_common_substring(arr1, arr2):
            
            delimiter = max(max(arr1), max(arr2)) + 1  
            arr = arr1 + [delimiter] + arr2
            n1 = len(arr1)

           
            suffix_array = suffix_array_construction(arr)

            lcp = lcp_array_construction(arr, suffix_array)

           
            max_len = 0

            for i in range(1, len(arr)):
                # Check if the consecutive suffixes belong to different original arrays
                if (suffix_array[i] < n1 and suffix_array[i - 1] > n1) or (suffix_array[i] > n1 and suffix_array[i - 1] < n1):
                    max_len = max(max_len, lcp[i])

            return max_len

        
        return longest_common_substring(nums1, nums2)

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