leetCode: Longest Repeating Character Replacement

Tito Owolabi — Thu, 16 Jul 2026 11:05:50 +0000

longest repeating character replacement.

why would you even want to know this? why?
so, you could show your friends?
is that what this is?
oh, look, i can find the longest repeating chara-

get outta here.

now, that, that's said.
how do i solve this?

i've read the question and would just write how i understand it.
i have two things.
actually, i'm given two things and want to return one thing.

what else?
there's a string, s and an integer, k.
all this just feels like beating around the bush.

what am i supposed to do?
i have a string.

i can change characters in the string.
i can change a certain amount of times.

i think it's best i write down the things that are true from the question
then put it together to know what this is really saying.

i have a string, s
i have an integer, k
i want to replace characters in the string.
i can only replace with uppercase English characters.
i can perform up to k replacements.
i want to return the length of the longest substring containing the same letter i can get after performing the above operations.

this is a mouthful, what's it saying really?
i want to return the length of a substring.

simply put, i want to return a number.

but what is this number?
the length of the longest substring containing the same letter i can get after performing the above operations.

this is still crazy.

i want to return a number.
the number is the length of a substring.

what is this substring?
the substring is the longest substring containing the same letter i can get after performing the above operations.

what operations?
the character replacement?

oh, i see.
i want to replace characters in the original string s
in a way that it forms the longest substring of the same character?

i guess. what is a substring?
back to back characters.

i see.
so, the question is, given a string, s
where i can replace up to k characters
what's the length of the longest streak of the same character.

i omitted it, but it goes without saying,
the characters in the string s are all uppercase characters.

i swear, the writing on this leetcode joint drives me nuts.
what's wrong with saying:

there's a string that only contains uppercase characters.
you, John Cena, can replace any character you want with another uppercase character.
but you can't replace more than `k` times.

the goal is to create the longest streak of the same character.
and tell us how long that streak is.

DEV Community: Tito Owolabi

leetCode: Longest Repeating Character Replacement