Minimum Distance to Type a Word Using Two Fingers LeetCode solution in Java

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class Solution {
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  HashMap<Character, Integer[]> pos;
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  int[][][] memo;
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  int type(String word, int index, char finger1, char finger2) {
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    if (index == word.length()) return 0;
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    int ans = 9999999;
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    if (memo[index][finger1 - 'A'][finger2 - 'A'] != -1)
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      return memo[index][finger1 - 'A'][finger2 - 'A'];
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    if (finger1 == '[') {
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      ans = Math.min(ans, type(word, index + 1, word.charAt(index), finger2));
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    } else {
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      Integer[] prev = pos.get(finger1);
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      Integer[] curr = pos.get(word.charAt(index));
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      int dist = Math.abs(prev[0] - curr[0]) + Math.abs(prev[1] - curr[1]);
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      ans = Math.min(ans, type(word, index + 1, word.charAt(index), finger2) + dist);
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    }
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    if (finger2 == '[') {
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      ans = Math.min(ans, type(word, index + 1, finger1, word.charAt(index)));
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    } else {
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      Integer[] prev = pos.get(finger2);
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      Integer[] curr = pos.get(word.charAt(index));
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      int dist = Math.abs(prev[0] - curr[0]) + Math.abs(prev[1] - curr[1]);
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      ans = Math.min(ans, type(word, index + 1, finger1, word.charAt(index)) + dist);
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    }
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    memo[index][finger1 - 'A'][finger2 - 'A'] = ans;
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    return ans;
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  }
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  public int minimumDistance(String word) {
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    pos = new HashMap();
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    for (int i = 0; i < 26; i++) {
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      Integer[] coord = {i / 6, i % 6};
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      pos.put((char) ('A' + i), coord);
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    }
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    memo = new int[word.length()]['z' - 'a' + 3]['z' - 'a' + 3];
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    for (int[][] row : memo) {
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      for (int[] rowColumn : row) {
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        Arrays.fill(rowColumn, -1);
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      }
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    }
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    return type(word, 0, '[', '[');
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  }
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}