3307.js

/** ------------------------------------------------------------------------------
 * 
 * 3307. Find the K-th Character in String Game II
 * Topics: Bit Manipulation
 * https://leetcode.com/problems/find-the-k-th-character-in-string-game-ii/description/?envType=daily-question&envId=2025-07-04
 * 
 ------------------------------------------------------------------------------ */
var kthCharacter = function (k, operations) {
  let ans = 0
  while (k !== 1) {
    let t = Math.floor(Math.log2(k))
    if (Number(1n << BigInt(t)) === k) {
      t--
    }
    k -= Number(1n << BigInt(t))
    if (operations[t]) {
      ans++
    }
  }
  return String.fromCharCode("a".charCodeAt(0) + (ans % 26))
}

console.log(kthCharacter(5, [0, 0, 0]))