Leetcode Convert a number to hexadecimal

The original title link is here: https://leetcode.com/problems/convert-a-number-to-hexadecimal/

Topic:

Given an integer, write a algorithm to convert it to hexadecimal. For negative integer, the complement method is used.

Note:

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

Example 1:

Input:26output: "1a"

Example 2:

Input:-1output: "FFFFFFFF"

Exercises

Each of the 4 bits consists of a hexadecimal digit, each taking out the last 4 bits and 1111 doing bit arithmetic & getting a digit.

Num moves right 4 bits, here with >>> instead of >>. e.g.-1 of two ' s complement is represented as FFFFFFFF, 32 bits are all 1 bit. If the 1 bit with >> first does not move, the condition num!=0 of the while loop does not appear.

Time Complexity:o (1). Space:o (1).

AC Java:

1  Public classSolution {2      PublicString Tohex (intnum) {3         if(num = = 0){4             return"0";5         }6         7StringBuilder SB =NewStringBuilder ();8          while(num! = 0){9             intdigit = num & 0xf;TenSb.insert (0, digit<10?) (Char) (digit+ ' 0 '): (Char) (digit-10+ ' a ')); OneNum >>>= 4; A         } -         returnsb.tostring (); -     } the}

Leetcode Convert a number to hexadecimal