# 0405. Convert a Number to Hexadecimal

https://leetcode.com/problems/convert-a-number-to-hexadecimal

## Description

Given an integer `num`, return _a string representing its hexadecimal representation_. For negative integers, [two’s complement](https://en.wikipedia.org/wiki/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`

## ac

```java
```
