How should I practice Longest Repeating Character Replacement?

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

Is Longest Repeating Character Replacement 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 · String

Longest Repeating Character Replacement

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Problem statement

You are given a string s containing only uppercase English letters and an integer k. You may replace at most k characters in s with any other uppercase English letter.

Return the length of the longest substring that can contain only one repeated letter after at most k replacements.

Function

characterReplacement(s: String, k: int) → int

Examples

Example 1

s = "ABAB"k = 2return = 4

Replace both occurrences of A with B, or both occurrences of B with A. The entire string then contains one repeated letter.

Example 2

s = "AABABBA"k = 1return = 4

The substring AABA can become AAAA with one replacement, so a length of 4 is possible.

Constraints

1 <= s.length <= 100000
s contains only uppercase English letters.
0 <= k <= s.length