38 lines
1.1 KiB
Java
38 lines
1.1 KiB
Java
public class Roman {
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private static int decodeSingle(char letter) {
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switch(letter) {
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case 'M': return 1000;
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case 'D': return 500;
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case 'C': return 100;
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case 'L': return 50;
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case 'X': return 10;
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case 'V': return 5;
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case 'I': return 1;
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default: return 0;
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}
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}
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public static int decode(String roman) {
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int result = 0;
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String uRoman = roman.toUpperCase(); //case-insensitive
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for(int i = 0;i < uRoman.length() - 1;i++) {//loop over all but the last character
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//if this character has a lower value than the next character
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if (decodeSingle(uRoman.charAt(i)) < decodeSingle(uRoman.charAt(i+1))) {
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//subtract it
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result -= decodeSingle(uRoman.charAt(i));
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} else {
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//add it
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result += decodeSingle(uRoman.charAt(i));
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}
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}
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//decode the last character, which is always added
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result += decodeSingle(uRoman.charAt(uRoman.length()-1));
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return result;
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}
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public static void main(String[] args) {
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System.out.println(decode("MCMXC")); //1990
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System.out.println(decode("MMVIII")); //2008
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System.out.println(decode("MDCLXVI")); //1666
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}
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}
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