Java) 연습문제 2-1

package Java_18_2.src;

import java.util.HashMap;

public class Practice1 {
    public static void solution(String s) {
        HashMap<Character, Integer> map = new HashMap<>();
        map.put('I', 1);
        map.put('V', 5);
        map.put('X', 10);
        map.put('L', 50);
        map.put('C', 100);
        map.put('D', 500);
        map.put('M', 1000);

        int sum = 0;
        char[] arr = s.toCharArray();
        for (int i = 0; i < arr.length - 1; i++) {
            if (map.get(arr[i]) < map.get(arr[i + 1])) {
                sum -= map.get(arr[i]);
            } else {
                sum += map.get(arr[i]);
            }
        }
        // 마지막 값은 for문 연산에 포함이 안되므로 따로 작성
        sum += map.get(arr[arr.length - 1]);
        System.out.println(sum);

    }

    public static void main(String[] args) {
        // Test code
        solution("III");
        solution("IV");
        solution("VI");
        solution("XIII");
        solution("XXVI");
        solution("MCMXCIV");
    }
}

 

 

 

 

package Java_18_2.src;

public class Practice2 {

    public static String solution(int num){
        String result = "";

        String[] roman = {"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"};
        int[] values = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};

        int i = 0;
        while (num > 0) {
            while (num >= values[i]) {
                num -= values[i];
                result += roman[i];
            }
            i++;
        }
        return result;
    }

    public static void main(String[] args) {
        // Test code
        System.out.println(solution(3));
        System.out.println(solution(4));
        System.out.println(solution(6));
        System.out.println(solution(13));
        System.out.println(solution(26));
        System.out.println(solution(1994));
    }
}