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Create a RomanNumerals class that can convert a roman numeral to and from an integer value. It should follow the API demonstrated in the examples below. Multiple roman numeral values will be tested for each helper method.
Modern Roman numerals are written by expressing each digit separately starting with the left most digit and skipping any digit with a value of zero. In Roman numerals 1990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC. 2008 is written as 2000=MM, 8=VIII; or MMVIII. 1666 uses each Roman symbol in descending order: MDCLXVI.
Input range : 1 <= n < 4000
In this kata 4 should be represented as IV, NOT as IIII (the "watchmaker's four").
Examples
RomanNumerals.toRoman(1000) // should return 'M'
RomanNumerals.fromRoman("M") // should return 1000Help
SymbolValue
| I | 1 |
| IV | 4 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
Solution
public class RomanNum {
public static String toRoman(int n) {
int a,b,c,d=0;
StringBuffer sb = new StringBuffer();
a = n/1000;
b = (n-a*1000)/100;
c = (n-a*1000-b*100)/10;
d = n-a*1000-b*100-c*10;
if(a>0){
for(int i = 0; i<a; i++){
sb.append("M");
}
}
if(b>0){
if(0<b && b<4){
for(int i = 0; i<b; i++){ sb.append("C");}
}
else if(b==4){sb.append("CD");}
else if(b==5){sb.append("D");}
else if(5<b && b<9){
sb.append("D");
for(int i = 0; i<b-5; i++){ sb.append("C");}
}
else if(b==9){sb.append("CM");}
}
if(c>0){
if(0<c && c<4){
for(int i = 0; i<c; i++){ sb.append("X");}
}
else if(c==4){sb.append("XL");}
else if(c==5){sb.append("L");}
else if(5<c && c<9){
sb.append("L");
for(int i = 0; i<c-5; i++){ sb.append("X");}
}
else if(c==9){sb.append("XC");}
}
if(d>0){
if(0<d && d<4){
for(int i = 0; i<d; i++){ sb.append("I");}
}
else if(d==4){sb.append("IV");}
else if(d==5){sb.append("V");}
else if(5<d && d<9){
sb.append("V");
for(int i = 0; i<d-5; i++){ sb.append("I");}
}
else if(d==9){sb.append("IX");}
}
String result = sb.toString();
return result;
}
public static int fromRoman(String romanNumeral) {
int result = 0,vol = 0;
String[] romalNum = romanNumeral.split("");
String roma1 = null;
String roma2 = null;
String roma3 = null;
for(int i = 0; i<romalNum.length; i++){
System.out.println(romalNum[i]);
if(romalNum[i].contains("C")||romalNum[i].contains("D")){
vol = 100;
roma1 = "C";
roma2 = "D";
roma3 = "M";
}else if(romalNum[i].contains("X")||romalNum[i].contains("L")){
vol = 10;
roma1 = "X";
roma2 = "L";
roma3 = "C";
}else if(romalNum[i].contains("I")||romalNum[i].contains("V")){
vol = 1;
roma1 = "I";
roma2 = "V";
roma3 = "X";
}
if(romalNum[i].contains("M")){
result += 1000;
}
else if(romalNum[i].contains(roma1)){
result += vol;
try {
if(romalNum[i+1].contains(roma3)){
result += 8*vol;
i += 1;
continue;
}
else if(romalNum[i+1].contains(roma2)){
result += 3*vol;
i += 1;
continue;
}
else if(romalNum[i+1].contains(roma1)){
result +=vol;
if(romalNum[i+2].contains(roma1)){
result +=vol;
i += 2;
}else {
i += 1;
}
continue;
}
}catch(Exception e) {
i++;
}
}
else if(romalNum[i].contains(roma2)){
result +=5*vol;
try {
if(romalNum[i+1].contains(roma1)){
result += vol;
if(romalNum[i+2].contains(roma1)){
result += vol;
if(romalNum[i+3].contains(roma1)){
result += vol;
i += 3;
continue;
}
i += 2;
continue;
}
i += 1;
continue;
}
}catch(Exception e) {
i++;
break;
}
}
}
return result;
}
}
Best Solution
public class RomanNumBest {
private static final String[] ROMAN_NUMBERS = {"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"};
private static final int[] ARABIC_NUMBERS = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};
public static String toRoman(int n) {
int remainingValue = n;
StringBuilder result = new StringBuilder();
for (int i = 0; i < ARABIC_NUMBERS.length; i++) {
while (remainingValue >= ARABIC_NUMBERS[i]) {
remainingValue -= ARABIC_NUMBERS[i];
result.append(ROMAN_NUMBERS[i]);
}
}
return result.toString();
}
public static int fromRoman(String romanNumeral) {
String remainingValue = romanNumeral;
int result = 0;
for(int i = 0; i<ROMAN_NUMBERS.length; i++) {
while(remainingValue.startsWith(ROMAN_NUMBERS[i])) {
remainingValue = remainingValue.substring(ROMAN_NUMBERS[i].length(), remainingValue.length());
result += ARABIC_NUMBERS[i];
}
}
return result;
}
}
싱글톤을 이용해서 해결한 방법이다. 다음에는 이런 방법을 적용해서 문제를 풀어보자
