Is Convert a Number to Hexadecimal easy or hard?

Convert a Number to Hexadecimal is categorized as an Easy problem. The main challenge is understanding how hexadecimal digits correspond to 4-bit binary groups and handling negative numbers using two's complement representation.

Convert a Number to Hexadecimal Python/Java solution

Python, Java, C++, C#, JavaScript, and C implementations typically use a loop with bit masking and right shifts. Extract the last 4 bits using num & 0xf, map it to a hexadecimal character, append to the result, then shift the number right by 4 bits.

How to solve Convert a Number to Hexadecimal in O(1)?

Use bit manipulation with a 4-bit mask. Extract the lowest hexadecimal digit using num & 0xf, convert it to the corresponding character, then shift the number right by 4 bits. Repeat until the number becomes zero or up to 8 iterations for a 32-bit integer.

What is the best approach for Convert a Number to Hexadecimal?

The bitwise iteration method is the most efficient and commonly expected solution. It extracts hexadecimal digits using a mask (num & 0xf) and shifts the number right by 4 bits each step. Since a 32-bit integer produces at most 8 hex digits, the algorithm runs in O(1) time and constant space.

Is Convert a Number to Hexadecimal asked at Google/Amazon/Meta?

Bit manipulation and number representation problems like this appear in interviews at companies such as Amazon, Google, and Meta. They test understanding of binary operations, masking, and two's complement representation rather than relying on built-in conversion utilities.

What data structure is used in Convert a Number to Hexadecimal?

The solution primarily relies on bit manipulation rather than complex data structures. Most implementations use a simple character array or string builder to map values 0–15 to hexadecimal characters (0–9 and a–f).

What is the time complexity of Convert a Number to Hexadecimal?

The optimal bitwise approach runs in O(1) time because a 32-bit integer generates at most 8 hexadecimal digits. A mathematical divide-by-16 approach takes O(log16 n) time since the number shrinks by a factor of 16 at each step.

Description Solution Video 4:42

405. Convert a Number to Hexadecimal

Easy54.8% acceptance6 companies

Given a 32-bit integer num, return a string representing its hexadecimal representation. For negative integers, two’s complement method is used.

All the letters in the answer string should be lowercase characters, and there should not be any leading zeros in the answer except for the zero itself.

Note: You are not allowed to use any built-in library method to directly solve this problem.

Example 1:

Input: num = 26
Output: "1a"

Example 2:

Input: num = -1
Output: "ffffffff"

Constraints:

-2³¹ <= num <= 2³¹ - 1

Asked at 6 companies

Microsoft Meta Bloomberg

TCS

Google Amazon

Topics

Bit Manipulation Math

4:42

Still stuck?Read 3 approaches, or watch a walkthrough.

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1class Solution:
2    def toHex(self, num: int) -> str:
3        

Starter codePython 3Spaces: 4

Examples

Case 1Case 2

Input

-1

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