1
var pushDominoes = function (dominoes) {
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  let l = 0,
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    r = 1;
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  const arr = ("L" + dominoes + "R").split("");
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  while (l < arr.length - 1) {
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    while (arr[r] == ".") r++;
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    if (arr[l] == arr[r]) for (let i = l + 1; i < r; i++) arr[i] = arr[l];
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    if (arr[l] > arr[r])
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      for (let i = 1; i <= (r - l - 1) / 2; i++) {
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        arr[l + i] = "R";
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        arr[r - i] = "L";
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      }
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    l = r++;
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  }
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  return arr.slice(1, arr.length - 1).join("");
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};