Is Encode Number easy or hard?

Encode Number is classified as a medium problem because the implementation is simple once you discover the pattern. The challenge lies in recognizing that the encoded sequence matches binary(num + 1) with the leading bit removed.

Encode Number Python/Java solution

In Python or Java, compute num + 1, convert it to binary, and remove the first character. Python can use bin(num + 1)[3:], while Java can use Integer.toBinaryString(num + 1).substring(1). Both implementations run in O(log n) time.

How to solve Encode Number in O(log n)?

Add 1 to the given number, convert the result to binary, and remove the first bit. For example, if num = 23, then num + 1 = 24 and its binary representation is 11000. Removing the leading '1' gives 1000, which is the encoded value.

What is the best approach for Encode Number?

The optimal approach uses a bit manipulation observation: the encoded value equals the binary representation of num + 1 with the leading '1' removed. This avoids simulation and directly computes the result in O(log n) time. The method relies on properties of binary numbering.

Is Encode Number asked at Google/Amazon/Meta?

Encode Number represents the type of bit manipulation and binary pattern recognition problems commonly used in interviews at companies like Google, Amazon, and Meta. These questions test whether candidates can detect hidden relationships in binary representations.

What data structure is used in Encode Number?

The problem mainly relies on bit manipulation and string handling rather than complex data structures. The integer is converted to a binary string, and simple string slicing removes the leading bit to produce the encoded result.

What is the time complexity of Encode Number?

The optimal solution runs in O(log n) time because the algorithm converts num + 1 into its binary representation, which requires processing the number of bits in n. Space complexity is also O(log n) due to the output binary string.

Description Hints 2 Solution Video 13:23

1256. Encode Number

Medium70.0% acceptance1 companyPremium elsewhere, free here

Given a non-negative integer num, Return its encoding string.

The encoding is done by converting the integer to a string using a secret function that you should deduce from the following table:

Example 1:


Input: num = 23

Output: "1000"

Example 2:


Input: num = 107

Output: "101100"

Constraints:

0 <= num <= 10^9

Asked at 1 company

Quora

Topics

Hints open one at a time

Hint 1

Try to find the number of binary digits returned by the function.

Hint 2

The pattern is to start counting from zero after determining the number of binary digits.

13:23

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