Algorithm
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:
Ican be placed beforeV(5) andX(10) to make 4 and 9.Xcan be placed beforeL(50) andC(100) to make 40 and 90.Ccan be placed beforeD(500) andM(1000) to make 400 and 900.
Given an integer, convert it to a roman numeral.
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
Code Examples
#1 Code Example with C Programming
Code -
C Programming
typedef struct {
char *s;
int v;
} map_t;
const map_t map[] = {
{ "I", 1 },
{ "IV", 4 },
{ "V", 5 },
{ "IX", 9 },
{ "X", 10 },
{ "XL", 40 },
{ "L", 50 },
{ "XC", 90 },
{ "C", 100 },
{ "CD", 400 },
{ "D", 500 },
{ "CM", 900 },
{ "M", 1000 }
};
#define SZ (sizeof(map)/sizeof(map[0]))
char* intToRoman(int num) {
int n, l = SZ - 1;
char *p = malloc(1024);
//assert(p);
p[0] = 0;
while (num) {
n = num / map[l].v;
while (n) {
strcat(p, map[l].s);
n --;
}
num = num % map[l].v;
l --;
}
return p;
}
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#2 Code Example with C++ Programming
Code -
C++ Programming
class Solution {
public:
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];
}
};
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#3 Code Example with Java Programming
Code -
Java Programming
class Solution {
private static final int[] values = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};
private static final String[] symbols = {
"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"};
public String intToRoman(int num) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < values.length && num > 0; i++) {
int factor = num / values[i];
num %= values[i];
if (factor > 0) {
for (int j = 1; j < = factor; j++) {
sb.append(symbols[i]);
}
}
}
return sb.toString();
}
}
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#4 Code Example with Javascript Programming
Code -
Javascript Programming
const map = {
"1000": "M",
"900": "CM",
"500": "D",
"400": "CD",
"100": "C",
"90": "XC",
"50": "L",
"40": "XL",
"10": "X",
"9": "IX",
"5": "V",
"4": "IV",
"1": "I"
};
const intToRoman = function(number) {
const l = fkey(map, number);
if (number == +l) {
return map[number];
}
return map[l] + intToRoman(number - +l);
};
function fkey(m, num) {
const keys = Object.keys(m);
const sArr = keys.filter(el => +el < = num);
return +Math.max.apply(Math, sArr);
}
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#5 Code Example with Python Programming
Code -
Python Programming
class Solution:
def intToRoman(self, num):
s = "M" * (num // 1000)
s += "CM" if num % 1000 >= 900 else "D" *((num % 1000) // 500)
s += "CD" if num % 500 >= 400 and s[-2:] != "CM" else "C" * ((num % 500) // 100) if num % 500 < 400 else ""
s += "XC" if num % 100 >= 90 else "L" * ((num % 100) // 50)
s += "XL" if num % 50 >= 40 and s[-2:] != "XC" else "X" * ((num % 50) // 10) if num % 50 < 40 else ""
s += "IX" if num % 10 >= 9 else "V" * ((num % 10) // 5)
s += "IV" if num % 5 >= 4 and s[-2:] != "IX" else "I" * ((num % 5) // 1) if num % 5 < 4 else ""
return s
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#6 Code Example with C# Programming
Code -
C# Programming
using System.Text;
namespace LeetCode
{
public class _012_IntegerToRoman
{
public string IntToRoman(int num)
{
string[] symbol = { "MMM", "MM", "M", "CM", "DCCC", "DCC", "DC", "D", "CD", "CCC", "CC", "C", "XC", "LXXX", "LXX", "LX", "L", "XL", "XXX", "XX", "X", "IX", "VIII", "VII", "VI", "V", "IV", "III", "II", "I" };
int[] value = { 3000, 2000, 1000, 900, 800, 700, 600, 500, 400, 300, 200, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 };
var result = new StringBuilder();
var index = 0;
while (num != 0)
{
if (num >= value[index])
{
num -= value[index];
result.Append(symbol[index]);
}
else
{
index++;
}
}
return result.ToString();
}
}
}
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