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.
```

**Solution:**

Simple check from 1000 to 900 to 500 to 400 to 100 …

```
class Solution {
public:
string intToRoman(int num) {
string ans = "";
while(num>=1000){
ans += 'M';
num -= 1000;
}
if(num>=900){
ans += "CM";
num -= 900;
}
if(num>=500){
ans += "D";
num -= 500;
}
if(num>=400){
ans += "CD";
num -= 400;
}
while(num>=100){
ans += "C";
num -= 100;
}
if(num >= 90){
ans += "XC";
num -= 90;
}
if(num >= 50){
ans += "L";
num -= 50;
}
if(num >= 40){
ans += "XL";
num -= 40;
}
while(num>=10){
ans += "X";
num -= 10;
}
if(num>=9){
ans += "IX";
num -= 9;
}
if(num>=5){
ans += "V";
num -= 5;
}
if(num >= 4){
ans += "IV";
num -= 4;
}
while(num){
ans += "I";
num--;
}
return ans;
}
};
```