DSA/RomantoInteger.java at main · aarushsing/DSA · GitHub

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public class RomantoInteger {
    public static void main(String[] args){
        romanToInt("XCVV");
        System.out.println(romanToInt("XCVI"));


    }


    public static int romanToInt(String s) {
    if(s == null){
        return 0;
    }

    int length = s.length();
    int sum = 0;
    int pre = 0;

    for(int i = length - 1; i >= 0; i--){
        int cur = romanTable(s.charAt(i));

        if(i == length - 1){
            sum = sum + cur;
        }else{
           if(cur < pre){
               sum = sum - cur;
           }else{
               sum = sum + cur;
           }
        }
        pre = cur;
    }

    return sum;
    }

    public static int romanTable(char c){
    int num = 0;
    switch(c){
        case 'I':
            num = 1;
            break;
        case 'V':
            num = 5;
            break;
         case 'X':
            num = 10;
            break;
         case 'L':
             num = 50;
             break;
         case 'C':
             num = 100;
             break;
         case 'D':
             num = 500;
             break;
         case 'M':
             num = 1000;
             break;
         default:
             num = 0;
             break;
    }
    return num;
}


    @Override
    public String toString() {
        return "RomantoInteger []";
    }

}