leetcode

// 3304. Find the K-th Character in String Game I
#include "leetcode.h"

/*
 * alice and bob are playing a game. initially, alice has a string 'word = "a"'.
 * you are given a positive integer 'k'. now, bob will ask alice to perform the
 * following operation forwever: generate a new string by changing each
 * character in 'word' to its next character in the english alphabet and append
 * it to the original 'word'. return the value of the k'th character in 'word'
 * after enough operations have been done for 'word' to have at least 'k'
 * characters. note that character 'z' can be changed to 'a' in the operation.
 */

char kthCharacter(int k) { return 'a' + __builtin_popcount(k - 1); }

int main() {
  printf("%c\n", kthCharacter(5));  // expect: b
  printf("%c\n", kthCharacter(10)); // expect: c
}