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Different Rightmost Bit

Description

Implement the missing code, denoted by ellipses. You may not modify the pre-existing code.

You’re given two integers, n and m. Find position of the rightmost bit in which they differ in their binary representations (it is guaranteed that such a bit exists), counting from right to left.

Return the value of 2position_of_the_found_bit (0-based).

Example

  • For n = 11 and m = 13, the output should be differentRightmostBit(n, m) = 2.

1110 = 10112, 1310 = 11012, the rightmost bit in which they differ is the bit at position 1 (0-based) from the right in the binary representations. So the answer is 21 = 2.

  • For n = 7 and m = 23, the output should be differentRightmostBit(n, m) = 16.

710 = 1112, 2310 = 101112, i.e.

00111 10111

So the answer is 24 = 16.

Input/Output

  • [execution time limit] 4 seconds (js)

  • [input] integer n

    Guaranteed constraints:
    0 \leq m \leq 2^{30}.
    n ≠ m.

  • [output] integer

[JavaScript (ES6)] Syntax Tips

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// Prints help message to the console
// Returns a string
function helloWorld(name) {
console.log("This prints to the console when you Run Tests");
return "Hello, " + name;
}

Solution

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function differentRightmostBit(n, m) {
  return (
    1 <<
    (n ^ m)
      .toString(2)
      .split("")
      .reverse()
      .join("")
      .indexOf("1")
  );
}