1
var checkPalindromeFormation = function (a, b) {
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  function isPal(str, l, r) {
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    while (l < r) {
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      if (str[l] === str[r]) l++, r--;
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      else return false;
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    }
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    return true;
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  }
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  // aprefix + bsuffix
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  let l = 0,
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    r = b.length - 1;
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  while (l < r && a[l] === b[r]) l++, r--;
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  if (isPal(a, l, r) || isPal(b, l, r)) return true;
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  // bprefix + asuffix
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  (l = 0), (r = a.length - 1);
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  while (l < r && b[l] === a[r]) l++, r--;
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  if (isPal(a, l, r) || isPal(b, l, r)) return true;
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  return false;
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};