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<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JS Bin</title>
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<body>
  <script>
    /* Returns if a text is a palindrome */
    function isPalindrome(text) {
      let valid = true;
      // Iterate over half of the characters
      for (var i = 0; i < text.length / 2; i++) {
        if (text.charAt(i) !== text.charAt(text.length - i - 1)) valid = false;
      }

      // Returns if its valid
      return valid;
    }

    /* Returns the character code at the position */
    function getCharCode(text, pos) {
      return text.charCodeAt(pos) - 'a'.charCodeAt(0);
    }

    /* Returns if a text is a permutation of a palindrome */
    function isPermutationofPalindrome(text) {
      const hash = new Array(26);
      // Goes over each character
      for (let i = 0; i < text.length; i++) {
        const charCode = getCharCode(text, i);
        hash[charCode] = (hash[charCode] || 0) + 1;
      }
      // Counts the number of characters that appear even times
      let evenCount = 0;
      for (let i = 0; i < hash.length; i++) {
        if (hash[i] % 2 === 1) evenCount += 1;
      }
      // It can be a palindrome if there is at most one even character
      return evenCount <= 1;
    }

    // Test
    //const word = 'catac';
    const word = 'xyz';
    document.write(`${word}:<br/>`);
    document.write(`isPalindrome: ${isPalindrome(word)}<br/>`);
    document.write(`isPermutationofPalindrome: ${isPermutationofPalindrome(word)}<br/>`);
  </script>


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