# leetcode 12. Integer to Roman

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, two is written as `II` in Roman numeral, just two one‘s added together. Twelve is written as, `XII`, which is simply `X` + `II`. The number twenty seven 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. Input is guaranteed to be within the range from 1 to 3999.

Example 1:

```Input: 3
Output: "III"```

Example 2:

```Input: 4
Output: "IV"```

Example 3:

```Input: 9
Output: "IX"```

Example 4:

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

Example 5:

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

```class Solution {
public String intToRoman(int num) {
int w4 = num % 10;
int w3 = (num/10) % 10;
int w2 = (num/100) % 10;
int w1 = (num/1000) % 10;
String res = "";

if(w1>0) {
for(int i=0; i<w1; i++) res += "M";
}

if(w2>0 && w2<4) {
for(int i=0; i<w2; i++) res += "C";
}else if(w2 == 4) {
res += "CD";
}else if(w2 == 9) {
res += "CM";
}else if(w2 != 0){
res += "D";
for(int i=0; i<w2-5; i++) res += "C";
}

if(w3>0 && w3<4) {
for(int i=0; i<w3; i++) res += "X";
}else if(w3 == 4) {
res += "XL";
}else if(w3 == 9) {
res += "XC";
}else if(w3 != 0){
res += "L";
for(int i=0; i<w3-5; i++) res += "X";
}

if(w4>0 && w4<4) {
for(int i=0; i<w4; i++) res += "I";
}else if(w4 == 4) {
res += "IV";
}else if(w4 == 9) {
res += "IX";
}else if(w4 != 0){
res += "V";
for(int i=0; i<w4-5; i++) res += "I";
}
return res;

}
}```

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

leetcode 12. Integer to Roman

(0)
(0)

0条

© 2014 bubuko.com 版权所有 鲁ICP备09046678号-4 