Longest Palindrome by Concatenating Two Letter Words LeetCode solution in Java

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class Solution {
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  public int longestPalindrome(String[] words) {
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    int[][] freq = new int[26][26]; // array for all alphabet combinations
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    for (String word : words)
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      freq[word.charAt(0) - 'a'][
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          word.charAt(1) - 'a']++; // here we first increase the freq for every word
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    int left = 0; // to store freq counts
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    boolean odd = false;
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    for (int i = 0; i != 26; i++) { // iterate over our array
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      odd |= (freq[i][i] & 1) == 1; // means odd number of freq for similar words are there
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      left += freq[i][i] / 2;
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      for (int j = i + 1; j != 26; j++) // nested iteration to find non similar pairs
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      left += Math.min(freq[i][j], freq[j][i]); // taking min times from both present
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    }
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    int res = left * 2 * 2; // res from total freq found!!
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    if (odd) {
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      res += 2; // if odd then adding 2
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    }
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    return res;
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  }
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}