Is Guess the Number Using Bitwise Questions II easy or hard?

The problem is rated Medium because the implementation is simple once the idea is clear, but the key insight is recognizing that each bit can be determined independently through queries. Candidates unfamiliar with bitwise reasoning or interactive patterns may initially find it tricky.

Guess the Number Using Bitwise Questions II Python/Java solution

The implementation is nearly identical across Python, Java, C++, and Go. Iterate through each bit position, construct a mask using a left shift, send the interactive query, and update the result using bitwise OR if the response indicates the bit is set. Each language handles bit operations efficiently, keeping the solution concise.

How to solve Guess the Number Using Bitwise Questions II in O(log n)?

Use bitwise masking to check each bit individually. Construct a query mask like (1 << i) and send it to the interactive system. The response indicates whether the hidden number contributes that bit under the defined operation. Update the answer using bitwise OR and repeat for all bit positions, resulting in O(log n) queries.

What is the best approach for Guess the Number Using Bitwise Questions II?

The optimal approach reconstructs the hidden value one bit at a time using bit manipulation. For each bit position, you send a query with a mask that isolates that bit and analyze the response. This reveals whether the bit is set in the secret number. Repeating this for all bit positions determines the full number in O(log M) queries with O(1) space.

Is Guess the Number Using Bitwise Questions II asked at Google/Amazon/Meta?

Problems involving bit manipulation and interactive queries appear frequently in interviews at companies like Google, Amazon, and Meta. While this exact problem may not appear verbatim, the pattern of reconstructing values using bitwise operations and minimal queries is a common interview theme.

What data structure is used in Guess the Number Using Bitwise Questions II?

The solution primarily uses bit manipulation rather than complex data structures. A single integer stores the reconstructed answer, and bit masks generated with shifts (1 << i) isolate individual positions. The logic relies on bitwise operations such as OR and shifting.

What is the time complexity of Guess the Number Using Bitwise Questions II?

The optimal solution runs in O(log M) time, where M is the maximum possible value of the hidden number. Each query determines information about a single bit, and integers typically have around 30–32 relevant bits. Space complexity remains O(1) because only the reconstructed answer and temporary masks are stored.

Description Hints 5 Solution Video 5:34

3094. Guess the Number Using Bitwise Questions II

Q: What is the best approach for Guess the Number Using Bitwise Questions II?

The optimal approach reconstructs the hidden value one bit at a time using bit manipulation. For each bit position, you send a query with a mask that isolates that bit and analyze the response. This reveals whether the bit is set in the secret number. Repeating this for all bit positions determines the full number in O(log M) queries with O(1) space.

Q: Is Guess the Number Using Bitwise Questions II asked at Google/Amazon/Meta?

Problems involving bit manipulation and interactive queries appear frequently in interviews at companies like Google, Amazon, and Meta. While this exact problem may not appear verbatim, the pattern of reconstructing values using bitwise operations and minimal queries is a common interview theme.

Q: What data structure is used in Guess the Number Using Bitwise Questions II?

The solution primarily uses bit manipulation rather than complex data structures. A single integer stores the reconstructed answer, and bit masks generated with shifts (1 << i) isolate individual positions. The logic relies on bitwise operations such as OR and shifting.

Q: What is the time complexity of Guess the Number Using Bitwise Questions II?

The optimal solution runs in O(log M) time, where M is the maximum possible value of the hidden number. Each query determines information about a single bit, and integers typically have around 30–32 relevant bits. Space complexity remains O(1) because only the reconstructed answer and temporary masks are stored.

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There is a number n between 0 and 2³⁰ - 1 (both inclusive) that you have to find.

There is a pre-defined API int commonBits(int num) that helps you with your mission. But here is the challenge, every time you call this function, n changes in some way. But keep in mind, that you have to find the initial value of n.

commonBits(int num) acts as follows:

Calculate count which is the number of bits where both n and num have the same value in that position of their binary representation.
n = n XOR num
Return count.

Return the number n.

Note: In this world, all numbers are between 0 and 2³⁰ - 1 (both inclusive), thus for counting common bits, we see only the first 30 bits of those numbers.

Constraints:

0 <= n <= 2³⁰ - 1
0 <= num <= 2³⁰ - 1
If you ask for some num out of the given range, the output wouldn't be reliable.

Topics

Bit Manipulation Interactive

Hints open one at a time

Hint 1

Ask the number 0 and save the result in base.

Hint 2

Ask 2ⁱ for 0 <= i < 30.

Hint 3

If the result is greater than base for some i, then this bit is a set bit in n.

Hint 4

What can be done to revert the effect of the XOR.

Hint 5

Doing XOR again with the same number reverts the effect.

5:34

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