How should I practice Longest Substring With At Most Two Distinct Characters?

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

Is Longest Substring With At Most Two Distinct Characters associated with ByteDance?

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

Problem · Sliding Window

Longest Substring With At Most Two Distinct Characters

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Problem statement

Given a string s, return the length of its longest contiguous substring containing at most two distinct characters.

A substring must occupy consecutive positions. Repeated occurrences of one character count as one distinct character. An empty string has answer 0.

Function

longestTwoDistinct(s: String) → int

Examples

Example 1

s = "eceba"return = 3

The substring ece has length 3 and uses only e and c. Every longer substring contains at least three distinct characters.

Example 2

s = "ccaabbb"return = 5

The substring aabbb has length 5. Adding either preceding c would introduce a third distinct character.

Constraints

0 <= s.length <= 50000
s contains only lowercase English letters.