Is LeetCode 188 allowing short?

Is LeetCode 188 Allowing Short Answers?

Understanding the Question

LeetCode is a popular platform for practicing coding challenges, and one of the most infamous ones is 188. This problem is notorious for its difficulty and has been a source of frustration for many programmers. The question at the heart of this article is whether LeetCode 188 allows short answers.

What is LeetCode 188?

Before we dive into the question, let’s quickly review what LeetCode 188 is. This problem is part of the LeetCode platform’s Easy category, which means it’s a relatively straightforward problem that requires basic programming skills. The problem statement is as follows:

Problem Statement

Given a linked list of integers, find the length of the longest substring without repeating elements.

Constraints

• The linked list contains at most 30 nodes.
• The linked list contains at most 30 nodes.
• The linked list contains at most 30 nodes.

Example

• Input: 1 -> 2 -> 3 -> 4 -> 5
• Output: 5

Solution

The solution to this problem involves using a sliding window approach with a set data structure to keep track of unique elements in the current substring. Here’s a step-by-step breakdown of the solution:

• Initialize an empty set to store unique elements in the current substring.
• Initialize two pointers, left and right, to the start of the linked list.
• Iterate through the linked list using the right pointer.
• For each node, check if the node is already in the set. If it is, remove the node from the set and move the left pointer to the right of the node.
• If the node is not in the set, add it to the set and move the right pointer to the right.
• After iterating through the entire linked list, the length of the longest substring without repeating elements is the size of the set.

Code

Here’s the code for the solution:

class ListNode:

    def __init__(self, x):

        self.val = x

        self.next = None



def longestSubarray(nums):

    # Initialize an empty set to store unique elements in the current substring

    unique_elements = set()

    # Initialize two pointers, left and right, to the start of the linked list

    left = 0

    # Initialize the maximum length of the substring without repeating elements

    max_length = 0

    # Iterate through the linked list using the right pointer

    for right in range(len(nums)):

        # While the node is in the set, remove the node from the set and move the left pointer to the right

        while nums[right] in unique_elements:

            unique_elements.remove(nums[left])

            left += 1

        # Add the node to the set

        unique_elements.add(nums[right])

        # Update the maximum length of the substring without repeating elements

        max_length = max(max_length, right - left + 1)

    return max_length

Is LeetCode 188 Allowing Short Answers?

The question at the heart of this article is whether LeetCode 188 allows short answers. To answer this question, we need to consider the constraints of the problem.

• The linked list contains at most 30 nodes.
• The linked list contains at most 30 nodes.
• The linked list contains at most 30 nodes.

Given these constraints, it’s clear that the solution to this problem cannot be optimized to produce a shorter answer. The solution requires iterating through the linked list and keeping track of unique elements in the current substring, which takes O(n) time.

However, there is a subtle point to consider. The question asks whether LeetCode 188 allows short answers, which implies that the answer is yes or no. The answer is no, because the solution to this problem cannot be optimized to produce a shorter answer.

Conclusion

In conclusion, LeetCode 188 is a problem that requires a straightforward solution that cannot be optimized to produce a shorter answer. The solution involves using a sliding window approach with a set data structure to keep track of unique elements in the current substring, which takes O(n) time. Therefore, the answer to the question is no, LeetCode 188 does not allow short answers.

Table

Constraint	Description
Linked list size	At most 30 nodes
Linked list size	At most 30 nodes
Linked list size	At most 30 nodes

Example Use Case

Here’s an example use case for the solution:

# Create a linked list: 1 -> 2 -> 3 -> 4 -> 5

head = ListNode(1)

head.next = ListNode(2)

head.next.next = ListNode(3)

head.next.next.next = ListNode(4)

head.next.next.next.next = ListNode(5)



# Find the length of the longest substring without repeating elements

length = longestSubarray([1, 2, 3, 4, 5])

print(length)  # Output: 5

This example demonstrates how to use the solution to find the length of the longest substring without repeating elements in a linked list.