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<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Cube — binary search</title>
</head>
<body>
  <h1>Binary search cube root</h1>
  <p>Edit <code>samples</code>, then click <strong>Run</strong>.</p>
  <pre id="out"></pre>
  <script>
    (function () {
      function isCubeBinary(n) {
        var x = Math.abs(n);
        var lo = 0;
        var hi = x;
        while (lo <= hi) {
          var mid = Math.floor((lo + hi) / 2);
          var cube = mid * mid * mid;
          if (cube === x) {
            return true;
          }
          if (cube < x) {
            lo = mid + 1;
          } else {
            hi = mid - 1;
          }
        }
        return false;
      }
      var samples = [27, 28, -8, 0, 64];
      var lines = [];
      for (var i = 0; i < samples.length; i++) {
        var value = samples[i];
        lines.push(value + ": " + (isCubeBinary(value) ? "cube" : "not a cube"));
      }
      document.getElementById("out").textContent = lines.join("\n");
    })();
  </script>
</body>
</html>

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JavaScript Cube Number — binary search (Try It)