3445.js

/** ------------------------------------------------------------------------------
 * 
 * 릿코드 제목
 * Topics: 토픽
 * https://leetcode.com/problems/maximum-difference-between-even-and-odd-frequency-ii/description/?envType=daily-question&envId=2025-06-11
 * 
 ------------------------------------------------------------------------------ */
var maxDifference = function (s, k) {
  const n = s.length
  let ans = -Infinity

  const getStatus = (cnt_a, cnt_b) => {
    return ((cnt_a & 1) << 1) | (cnt_b & 1)
  }

  for (const a of ["0", "1", "2", "3", "4", "5"]) {
    for (const b of ["0", "1", "2", "3", "4", "5"]) {
      if (a === b) {
        continue
      }
      const best = [Infinity, Infinity, Infinity, Infinity]
      let cnt_a = 0,
        cnt_b = 0
      let prev_a = 0,
        prev_b = 0
      let left = -1

      for (let right = 0; right < n; right++) {
        cnt_a += s[right] === a ? 1 : 0
        cnt_b += s[right] === b ? 1 : 0

        while (right - left >= k && cnt_b - prev_b >= 2) {
          const left_status = getStatus(prev_a, prev_b)
          best[left_status] = Math.min(best[left_status], prev_a - prev_b)
          left++
          prev_a += s[left] === a ? 1 : 0
          prev_b += s[left] === b ? 1 : 0
        }

        const right_status = getStatus(cnt_a, cnt_b)
        if (best[right_status ^ 0b10] !== Infinity) {
          ans = Math.max(ans, cnt_a - cnt_b - best[right_status ^ 0b10])
        }
      }
    }
  }
  return ans
}

console.log()