1271. Hexspeak π
Description
A decimal number can be converted to its Hexspeak representation by first converting it to an uppercase hexadecimal string, then replacing all occurrences of the digit '0'
with the letter 'O'
, and the digit '1'
with the letter 'I'
. Such a representation is valid if and only if it consists only of the letters in the set {'A', 'B', 'C', 'D', 'E', 'F', 'I', 'O'}
.
Given a string num
representing a decimal integer n
, return the Hexspeak representation of n
if it is valid, otherwise return "ERROR"
.
Example 1:
Input: num = "257" Output: "IOI" Explanation: 257 is 101 in hexadecimal.
Example 2:
Input: num = "3" Output: "ERROR"
Constraints:
1 <= num.length <= 12
num
does not contain leading zeros.- num represents an integer in the range
[1, 1012]
.
Solutions
Solution 1: Simulation
Convert the number to a hexadecimal string, then traverse the string, convert the number $0$ to the letter $O$, and the number $1$ to the letter $I$. Finally, check whether the converted string is valid.
The time complexity is $O(\log n)$, where $n$ is the size of the decimal number represented by $num$.
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