424.longest-repeating-character-replacement.js

/*
 * @lc app=leetcode id=424 lang=javascript
 *
 * [424] Longest Repeating Character Replacement
 */

// @lc code=start
/**
 * @param {string} s
 * @param {number} k
 * @return {number}
 */
var characterReplacement = (s, k) => {
  let left = 0;
  let right = 0;
  let maxCharCount = 0;
  const visited = {};

  while (right < s.length) {
    const char = s[right];
    visited[char] = visited[char] ? visited[char] + 1 : 1;

    maxCharCount = Math.max(visited[char], maxCharCount);

    if (right - left + 1 - maxCharCount > k) {
      visited[s[left]]--;
      left++;
    }

    right++;
  }

  return right - left;
};
// @lc code=end