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Program to find length of longest distinct sublist in Python

Suppose we have a list of numbers called nums, and we have to find the length of the longest contiguous sublist where all its elements are unique.

So, if the input is like nums = [6, 2, 4, 6, 3, 4, 5, 2], then the output will be 5, as the longest list of unique elements is [6, 3, 4, 5, 2].

To solve this, we will follow these steps −

  • head := 0, dct := a new map

  • max_dist := 0

  • for each index i and element num in nums, do

    • if num is in dct and dct[num] >= head, then

      • head := dct[num] + 1

    • dct[num] := i

    • if i - head + 1 > max_dist, then

      • max_dist := i - head + 1

  • return max_dist

Let us see the following implementation to get better understanding −

Example

class Solution:
   def solve(self, nums):
      head = 0
      dct = {}
      max_dist = 0
      for i, num in enumerate(nums):
         if num in dct and dct[num] >= head:
            head = dct[num] + 1
         dct[num] = i
         if i - head + 1 > max_dist:
            max_dist = i - head + 1
   return max_dist
ob = Solution()
nums = [6, 2, 4, 6, 3, 4, 5, 2]
print(ob.solve(nums))

Input

[6, 2, 4, 6, 3, 4, 5, 2]

Output

5