[LeetCode] 12. Integer to Roman (Java)

Description

Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.

Symbol       Value
I             1
V             5
X             10
L             50
C             100
D             500
M             1000

For example, 2 is written as II in Roman numeral, just two one's added together. 12 is written as XII, which is simply X + II. The number 27 is written as XXVII, which is XX + V + II.

Roman numerals are usually written largest to smallest from left to right. However, the numeral for four is not IIII. Instead, the number four is written as IV. Because the one is before the five we subtract it making four. The same principle applies to the number nine, which is written as IX. There are six instances where subtraction is used:

• I can be placed before V (5) and X (10) to make 4 and 9. 
• X can be placed before L (50) and C (100) to make 40 and 90. 
• C can be placed before D (500) and M (1000) to make 400 and 900.

Given an integer, convert it to a roman numeral.

 

주어진 정수를 로마자로 변환하기.

 

Example 1:

Input: num = 3
Output: "III"
Explanation: 3 is represented as 3 ones.

Example 2:

Input: num = 58
Output: "LVIII"
Explanation: L = 50, V = 5, III = 3.

Example 3:

Input: num = 1994
Output: "MCMXCIV"
Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.

 

Constraints:

• 1 <= num <= 3999

 

Solution

class Solution {
    public String intToRoman(int num) {
        String I[] = {"","I","II","III","IV","V","VI","VII","VIII","IX"};
        String X[] = {"","X","XX","XXX","XL","L","LX","LXX","LXXX","XC"};
        String C[] = {"","C","CC","CCC","CD","D","DC","DCC","DCCC","CM"};
        String M[] = {"","M","MM","MMM"};
        
        return M[num/1000]+C[num/100%10]+X[num/10%10]+I[num%10];
    }
}

내가 생각해낸 풀이는 아니고 for문으로 문제를 풀이 한 뒤 다른 사람들의 풀이를 찾다가 알게되었다.

언뜻보면 별 것 아닌 것 같지만 문제를 보자마자 for문과 if문을 사용한 풀이를 생각한 나와 다르게 깔끔하고 효율적으로 풀이된 코딩이 어떤 느낌인지 알게 된 것 같다...