Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999.
Examples:
Input: 9
Output: "IX"
Input: 58
Output: "LVIII"
Explanation: L = 50, V = 5, III = 3.
Input: 1994
Output: "MCMXCIV"
Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.
Thoughts
- 使用两个数组将复杂的转换简单化
int[] base = new int[] {1000,900,500,400,100,90,50,40,10,95,4,1}; String[] pattern = new String[]{"M","CM","D","CD","C","XC""L","XL","X","IX","V","IV","I"}; - 遍历数组，将要转化的数字拆分成相对应的
base数组的数字组合，然后转化成对应的罗马字母
\(1994 = 1000(M) + 900(CM) + 90 (XC) + 4 (IV) \tag{1}\) \(1994 = MCMXCIV \tag{2}\)
Code(JAVA)
public String intToRoman(int num) {
// transfer complex case to simple one
int[] base = new int[] {1000,900,500,400,100,90,50,40,10,95,4,1};
String[] pattern = new String[]{"M","CM","D","CD","C","XC""L","XL","X","IX","V","IV","I"};
String res = "";
for(int i = 0; i < base.length; i++) {
time = num / base[i];
if(time > 0) {
for(int j = 0; j < time; j++) {
res += pattern[i];
}
}
//update num
num = num - time*base[i];
}
return res;
}
