<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>

class HashSearch:

    def __init__(self, nums, max_length, prime):
        self.prime = prime
        self.mod = 1000000007
        self.hashes = [0]
        self.powers = [1]
        self.max_length = max_length
        for num in nums:
            self.hashes.append(((num + 1) * self.powers[-1] + self.hashes[-1]) % self.mod)
            self.powers.append((self.powers[-1] * self.prime) % self.mod)
        while len(self.powers) < max_length:
            self.powers.append((self.powers[-1] * self.prime) % self.mod)


    def get_hash(self, start_index, end_index):
        return ((self.hashes[end_index + 1] - self.hashes[start_index]) * self.powers[self.max_length - end_index - 1]) % self.mod

class DoubleHashSearch:

    def __init__(self, nums, max_length):
        self.hash1 = HashSearch(nums, max_length, 51)
        self.hash2 = HashSearch(nums, max_length, 53)

    def get_hash(self, start_index, end_index):
        return (self.hash1.get_hash(start_index, end_index), self.hash2.get_hash(start_index, end_index))

class Solution:
    def findLength(self, nums1: List[int], nums2: List[int]) -> int:
        if len(nums1) > len(nums2):
            nums1, nums2 = nums2, nums1
        nums1_hashes = DoubleHashSearch(nums1, len(nums2))
        nums2_hashes = DoubleHashSearch(nums2, len(nums2))
        left = 0
        right = len(nums1)
        while left < right:
            mid = (left + right + 1) // 2
            possible_hashes = set()
            is_mid_possible = False
            for start_index in range(len(nums1) - mid + 1):
                possible_hashes.add(nums1_hashes.get_hash(start_index, start_index + mid - 1))
            new_possible_hashes = set()
            for start_index in range(len(nums2) - mid + 1):
                new_possible_hashes.add(nums2_hashes.get_hash(start_index, start_index + mid - 1))
                if nums2_hashes.get_hash(start_index, start_index + mid - 1) in possible_hashes:
                    is_mid_possible = True
                    break
            if is_mid_possible:
                left = mid
            else:
                right = mid - 1
        return left
17600