2081.js

/** ------------------------------------------------------------------------------
 * 
 * 2081. Sum of k-Mirror Numbers
 * Topics: Math
 * https://leetcode.com/problems/sum-of-k-mirror-numbers/description/?envType=daily-question&envId=2025-06-23
 * 
 ------------------------------------------------------------------------------ */
const isPalindrome = (s) => {
  let n = s.length
  let i = 0
  let j = n - 1
  while (i < j) {
    if (s[i++] != s[j--]) return false
  }
  return true
}

/**
 * @param {number} k
 * @param {number} n
 * @return {number}
 */
var kMirror = function (k, n) {
  let res = 0
  for (let len = 1; ; len++) {
    let min = 10 ** ((len - 1) >> 1),
      max = 10 ** ((len + 1) >> 1)
    for (let base = min; base < max; base++) {
      let x = base
      for (let i = len & 1 ? parseInt(base / 10) : base; i > 0; i = int(i / 10)) {
        x = x * 10 + (i % 10)
      }
      let s = x.toString(k)
      if (isPalindrome(s)) {
        res += x
        n--
        if (!n) return res
      }
    }
  }
}

console.log(kMirror(2, 5))