#1271 - Hexspeak

Easy • View on LeetCode • View on GitHub

Problem 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".

Solution

/**
 * @param {string} num
 * @return {string}
 */
var toHexspeak = function(num) {
  const hex = BigInt(num).toString(16).toUpperCase();
  const validChars = new Set(['0', '1', 'A', 'B', 'C', 'D', 'E', 'F']);

  for (const char of hex) {
    if (!validChars.has(char)) {
      return 'ERROR';
    }
  }

  return hex.replace(/0/g, 'O').replace(/1/g, 'I');
};