Maximize Palindrome Length From Subsequences LeetCode solution in Java

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class Solution {
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  public int longestPalindrome(String word1, String word2) {
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    String lWord = word1 + word2;
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    return palindrome(
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        lWord,
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        0,
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        lWord.length() - 1,
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        word1.length(),
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        false,
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        new int[lWord.length()][lWord.length()][2]);
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  }
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  private int palindrome(
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      String word, int start, int end, int boundary, boolean isFound, int[][][] dp) {
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    if ((!isFound && (start >= boundary || end < boundary)) || (start > end)) return 0;
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    if (dp[start][end][isFound ? 0 : 1] != 0) return dp[start][end][isFound ? 0 : 1];
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    return dp[start][end][isFound ? 0 : 1] =
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        word.charAt(start) == word.charAt(end)
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            ? ((start == end ? 1 : 2) + palindrome(word, start + 1, end - 1, boundary, true, dp))
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            : Math.max(
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                palindrome(word, start + 1, end, boundary, isFound, dp),
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                palindrome(word, start, end - 1, boundary, isFound, dp));
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  }
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}