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/**
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 * @param {number} x
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 * @return {number}
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 */
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var mySqrt = function (x) {
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  const numx = x;
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  let num = 0;
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  while (num <= x) {
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    const avg = Math.floor((num + x) / 2);
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    if (avg * avg > numx) x = avg - 1;
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    else num = avg + 1;
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  }
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  return x;
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};