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"

 public class Solution {

     public String toHex(int num) {

         StringBuffer res = new StringBuffer();

         String[] charMap = new String[]{"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};

         for (int i=0; i<8; i++) {

             int number = num & (0b1111);

             num = num >>> 4;

             res.insert(0, charMap[number]);

         }

         while (res.charAt(0)=='0' && res.length()>1) res.deleteCharAt(0);

         return res.toString();

     }

 }

 public class Solution {

     public String toHex(int num) {

         if (num == 0) return "0";

         StringBuffer res = new StringBuffer();

         String[] charMap = new String[]{"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};

         while (num != 0) {

             int number = num & (0b1111);

             num = num >>> 4;

             res.insert(0, charMap[number]);

         }

         return res.toString();

     }

 }