Longest Substring With Unique Characters

Find the longest substring within a given string that contains no repeating characters. This tests your ability to efficiently manage string data and optimize for performance using sliding window techniques.

stringsliding windowsubstringhash setoptimization

Problem Statement

Given a string, determine the length of the longest substring that contains only distinct characters. In other words, find the longest sequence of characters within the string where each character appears only once.

Example 1

Input: dvdf

Output: 3

The longest substring with distinct characters is 'vdf', which has a length of 3.

Example 2

Input: abcabcbb

Output: 3

The longest substring with distinct characters is 'abc', which has a length of 3. Note that 'bca' or 'cab' would also work.

Constraints

-The input string can contain any ASCII characters.
-The length of the input string will be between 0 and 5 * 10^4.
-The substring must be contiguous (characters must be adjacent in the original string).

Brute Force Approach

Imagine you have a magnifying glass and want to examine every possible section of a text. The brute force approach involves checking every possible substring by starting at each index and expanding outwards, verifying each time if all the characters in that substring are unique. This method is slow because you are re-evaluating overlapping substrings. The time complexity is O(n^3) due to the nested loops for substring generation and the check for uniqueness, and the space complexity is O(1) as we only use constant extra space.

TimeO(n^3)

SpaceO(1)

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