Longest Repeating Character Replacement LeetCode solution in Java

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/** Time O(n) Space O(26) */
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class Solution {
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  public int characterReplacement(String s, int k) {
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    // Space O(26)
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    int[] dic = new int[26];
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    int start = 0;
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    int maxLen = 0;
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    // Time O(n)
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    for (int end = 0; end < s.length(); end++) {
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      maxLen = Math.max(maxLen, ++dic[s.charAt(end) - 'A']);
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      if (end - start + 1 > maxLen + k) {
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        dic[s.charAt(start) - 'A']--;
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        start++;
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      }
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    }
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    return s.length() - start;
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  }
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}