Convert A Number To Hexadecimal - Leetcode Solution

The problem "Convert A Number To Hexadecimal" on LeetCode asks us to convert an input integer to a hexadecimal string.

We can solve this problem by using the following steps:

Step 1: Define the hex digits We first need to define the hex digits from 0 to 9 and A to F. We can use a string array to define them.

Step 2: Convert to base 16 We can convert the input integer into its hexadecimal representation by repeatedly dividing it by 16 and taking the remainders. The remainders are the digits of the hexadecimal representation from right to left.

Step 3: Create the hexadecimal string We can create the final hexadecimal string by concatenating the hex digits obtained in step 2 in reverse order.

Here's the detailed solution in Python:

def toHex(num: int) -> str: # Define the hex digits hexDigits = "0123456789abcdef"

# Edge case: num is 0
if num == 0:
	return "0"

# Edge case: num is negative
if num < 0:
	# Convert to its 2's complement
	num = (2**32 + num)

# Convert to base 16
hexStr = ""
while num > 0:
	remainder = num % 16
	hexStr += hexDigits[remainder]
	num = num // 16
	
# Reverse the order of the hex digits
hexStr = hexStr[::-1]

return hexStr

The time complexity of this solution is O(log n), where n is the input integer, as we are repeatedly dividing the input by 16. The space complexity is O(1), as we are only using a constant amount of memory to store the hex digits.

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