Maximum Product of Word Lengths LeetCode solution in JavaScript

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/**
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 * @param {string[]} words
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 * @return {number}
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 */
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var maxProduct = function (words) {
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  words.sort((a, b) => b.length - a.length);
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  const m = new Map();
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  for (let word of words) {
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    if (m.has(word)) continue;
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    const alpha = new Array(26).fill(0);
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    for (let w of word) {
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      let idx = w.charCodeAt(0) - "a".charCodeAt(0);
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      alpha[idx] = 1;
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    }
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    m.set(word, parseInt(alpha.join(""), 2));
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  }
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  const hasCommonLetters = (a, b) => {
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    const sb = m.get(b);
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    const sa = m.get(a);
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    return (sa & sb) != 0;
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  };
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  let ans = 0,
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    len = words.length;
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  for (let i = 0; i < len; i++) {
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    for (let j = i + 1; j < len; j++) {
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      if (!hasCommonLetters(words[i], words[j])) {
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        ans = Math.max(ans, words[i].length * words[j].length);
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      }
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    }
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  }
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  return ans;
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};