Dsa
Strings
Medium
Minimal K-Periodic Edits
A string S is K-periodic if S[i] == S[i+K] for all valid i. Given an integer K and a string S, calculate the minimum number of character changes required to make the string K-periodic. You can change any character to any other uppercase letter.
Input format:
Line 1: The integer K
Line 2: The string S
Example:
Input:
2
ABCDE
Output: 3
(Possible result 'ABABA', changes C, D, E)
Key concepts
stringsfrequency countoptimization
Practise this out loud — free
Start a mock interview on THIS exact question — a voice AI interviewer opens with it, pushes back like a real onsite, then hands you an instant scorecard.
🎙 Practise this question now