How should I practice Longest Substring Without Repeating Characters?

Start by reading the full statement, solve the visible examples, then compare the pattern against related TikTok phone screen problems in FastPrep.

Is Longest Substring Without Repeating Characters associated with TikTok?

FastPrep tags this as a TikTok phone screen coding practice problem when the problem catalog has that company and stage context.

Longest Substring Without Repeating Characters

TikTok● MediumINTERNPHONE SCREEN

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Problem statement

Given a string text, return the length of its longest contiguous substring in which every character is distinct.

A substring keeps consecutive characters in their original order. Uppercase and lowercase letters are different characters, and spaces and punctuation also count. The empty string has answer 0.

Function

lengthOfLongestSubstring(text: String) → int

Examples

Example 1

text = "abcabcbb"return = 3

The substring abc has three distinct characters; no longer substring qualifies.

Example 2

text = "abba"return = 2

Either ab or ba has length two. The repeated letters cannot be skipped.

Example 3

text = ""return = 0

An empty string contains no nonempty substring.

Constraints

0 <= text.length <= 10000.
Every character is printable ASCII, with code from 32 through 126.