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

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const dist = function (from, to) {
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  if (from == -1) return 0;
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  const d1 = Math.abs(
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      ((from.charCodeAt(0) - 65) % 6) - ((to.charCodeAt(0) - 65) % 6)
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    ),
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    d2 = Math.abs(
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      Math.floor((from.charCodeAt(0) - 65) / 6) -
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        Math.floor((to.charCodeAt(0) - 65) / 6)
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    );
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  return d1 + d2;
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};
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var minimumDistance = function (word) {
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  const dp = new Map();
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  const dfs = function (i, lpos, rpos) {
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    if (i == word.length) return 0;
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    const key = [i, lpos, rpos].join(",");
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    if (dp.get(key)) return dp.get(key);
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    dp.set(
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      key,
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      Math.min(
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        dist(lpos, word[i]) + dfs(i + 1, word[i], rpos),
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        dist(rpos, word[i]) + dfs(i + 1, lpos, word[i])
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      )
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    );
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    return dp.get(key);
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  };
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  return dfs(0, -1, -1);
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};