LeetCode_405. Convert a Number to Hexadecimal

405. Convert a Number to Hexadecimal

Easy

Given an integer, write an algorithm to convert it to hexadecimal. For negative integer, two’s complement method is used.

Note:

All letters in hexadecimal (a-f) must be in lowercase.
The hexadecimal string must not contain extra leading 0s. If the number is zero, it is represented by a single zero character '0'; otherwise, the first character in the hexadecimal string will not be the zero character.
The given number is guaranteed to fit within the range of a 32-bit signed integer.
You must not use any method provided by the library which converts/formats the number to hex directly.

Example 1:

Input:

26

Output:

"1a"

Example 2:

Input:

-1

Output:

"ffffffff"

package leetcode.easy;

public class ConvertANumberToHexadecimal {

	char[] map = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

	@org.junit.Test

	public void test() {

		System.out.println(toHex(26));

		System.out.println(toHex(-1));

	}

	public String toHex(int num) {

		if (num == 0) {

			return "0";

		}

		String result = "";

		while (num != 0) {

			result = map[(num & 15)] + result;

			num = (num >>> 4);

		}

		return result;

	}

}

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LeetCode_405. Convert a Number to Hexadecimal

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