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var pseudoPalindromicPaths = function (root) {
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  if (!root) return 0;
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  // if even it's zero or it's power of two when odd
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  const ways = (r = root, d = 0) => {
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    if (!r) return 0;
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    d = d ^ (1 << r.val);
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    // leaf
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    if (r.left == r.right && r.left == null) {
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      const hasAllEven = d == 0;
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      const hasOneOdd = (d ^ (d & -d)) == 0;
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      return Number(hasEven || hasOneOdd);
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    }
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    return ways(r.left, d) + ways(r.right, d);
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  };
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  return ways();
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};