Leetcode # 65. Valid Number

https://leetcode.com/problems/valid-number

Solution

Time Complexity: O(len(s))
Space Complexity: O(1)
(The input and output generally do not count towards the space complexity.)

class Solution:
  def isNumber(self, s: str) -> bool:
    stack = ""
    for c in s:
      match c:
        case "E" | "e": # "e"
          stack += "e"
        case "+" | "-": # "s"
          stack += "s"
        case ".":
          stack += "."
        case _: # "d"
          o = ord(c)
          if o < 48 or o > 57:
            return False
          if stack == "" or stack[-1] != "d":
            stack += "d"
    
    pattern = {
       "D":["d.d", "d.", ".d"], 
       "N":["sD", "D"], 
       "I":["sd", "d"]
    }
    for key in ["D", "N", "I"]:
      for p in pattern[key]:
        stack = stack.replace(p, key)

    match stack:
      case "I" | "N" | "NeI" | "IeI":
        return True
    return False

Last Updated on 2023/08/16 by A1go