1653.js

/** ------------------------------------------------------------------------------
 * 
 * 1653. Minimum Deletions to Make String Balanced
 * Topics: DP Stack
 * https://leetcode.com/problems/minimum-deletions-to-make-string-balanced/description/?envType=daily-question&envId=2024-07-30
 * 
 ------------------------------------------------------------------------------ */
/**
 * @param {string} s
 * @return {number}
 */
var minimumDeletions = function (s) {
  let count = 0
  let prefix = 0

  for (let st of s) {
    if (st === "b") {
      prefix++
    } else if (st === "a" && prefix > 0) {
      prefix--
      count++
    }
  }

  return count
}

/** ------------------------------------------------------------------------------
 * 
 * 가장 직관적인 풀이
 * 스트링 종류는 a와 b 밖에없으므로 삼항연산자로 충분히 가능하다.
 * 
 ------------------------------------------------------------------------------ */
/**
 * @param {string} s
 * @return {number}
 */
var minimumDeletions = function (s) {
  let bCount = 0
  let count = 0
  for (let i = 0; i < s.length; i++) {
    s[i] === "b" ? bCount++ : (count = Math.min(count + 1, bCount))
  }
  return count
}