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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6.  
  7. /* Name of the class has to be "Main" only if the class is public. */
  8. class Ideone
  9. {
  10.     public enum RomanDigit {
  11.         i(1, true), v(5, false), x(10, true), l(50, false), c(100, true), d(500, false), m(1000, true);
  12.  
  13.         private int value;
  14.         private boolean repeatable;
  15.  
  16.         RomanDigit (int value, boolean repeatable){
  17.             this.value = value;
  18.             this.repeatable = repeatable;
  19.         }
  20.  
  21.         public int getValue() {
  22.             return value;
  23.         }
  24.  
  25.         public boolean isRepeatable() {
  26.             return repeatable;
  27.         }
  28.  
  29.         public boolean subtractableFrom(RomanDigit other) {
  30.             // Currently subtractale digits happen to be the same ones that are repeatable.
  31.             // Should this change, then another solution is needed.
  32.             if (other == null || !this.isRepeatable()) {
  33.                 return false;
  34.             }
  35.  
  36.             int oridinal = this.ordinal();
  37.             int otherOridinal = other.ordinal();
  38.  
  39.             return (oridinal == otherOridinal - 1 ||  oridinal == otherOridinal - 2);
  40.         }
  41.     }
  42.  
  43.     public static int convertRomanNumber(String romanNumber) {
  44.         RomanDigit previousDigit = null;
  45.         int characterRepeatCount = 1;
  46.         int total = 0;
  47.  
  48.         for(int i = 0; i < romanNumber.length(); i++){
  49.             // Also throws IllegalArgumentException if a digit is invalid
  50.             RomanDigit currentDigit = RomanDigit.valueOf(String.valueOf(romanNumber.charAt(i)));
  51.             int currentRomanCharNumericValue = currentDigit.getValue();
  52.  
  53.             if (currentDigit.equals(previousDigit)) {
  54.                 characterRepeatCount++;
  55.  
  56.                 if (characterRepeatCount > 3) {
  57.                     throw new IllegalArgumentException("Repeatable Digit is repeated too often"); // Error message needs more details
  58.                 }
  59.                 if (currentDigit.isRepeatable()) {
  60.                     total += currentRomanCharNumericValue;
  61.                 } else {
  62.                     throw new IllegalArgumentException("Unrepeatable Digit is repeated"); // Error message needs more details
  63.                 }
  64.             } else if (previousDigit != null && previousDigit.compareTo(currentDigit) < 0) {
  65.                 if (characterRepeatCount > 1) {
  66.                     throw new IllegalArgumentException("Repeatable Digit is repeated before larger digit"); // Error message needs more details
  67.                 }
  68.                 if (previousDigit.subtractableFrom(currentDigit)) {
  69.                     characterRepeatCount = 1;
  70.                     total += currentRomanCharNumericValue - (2 * previousDigit.getValue()); 
  71.                 } else {
  72.                     throw new IllegalArgumentException("Digit may not be subtracted from other digit"); // Error message needs more details
  73.                 }
  74.             } else {
  75.                 characterRepeatCount = 1;
  76.                 total += currentRomanCharNumericValue;
  77.             }
  78.  
  79.             previousDigit = currentDigit;
  80.         }
  81.         return total;
  82.     }
  83.  
  84.  
  85.     public static void main (String[] args) throws java.lang.Exception
  86.     {
  87.         try {
  88.             System.out.println( convertRomanNumber("ii") );
  89.             System.out.println( convertRomanNumber("iii") );
  90.             System.out.println( convertRomanNumber("iv") );
  91.             System.out.println( convertRomanNumber("vi") );
  92.             System.out.println( convertRomanNumber("ix") );
  93.             System.out.println( convertRomanNumber("mcmxliv") );
  94.         } catch(IllegalArgumentException e) {
  95.             // TODO handle Errors better
  96.             System.out.println( e.getMessage() );
  97.         }  
  98.  
  99.     }
  100. }
Success #stdin #stdout 0.04s 711168KB
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1944
https://ideone.com/AyEuL0
language:
Java (HotSpot 12)
created:
7 years ago
visibility:
public

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