## Roman Number to Integer

Question – Given a string in roman no format (s)  your task is to convert it to an integer. Various symbols and their values are given below.
I 1
V 5
X 10
L 50
C 100
D 500
M 1000

Example

Give Input: s = V Expected Output: 5

Logic

• Create a Hashmpa to store corresponding values
• Iterate over the string and compare the current character with the next one, so it’s greater than adding it to the sum otherwise need to subtract it.
• The last character is let un touched so we are adding in the last.
• Finally, return the sum.

Code

```class Solution {

public int romanToDecimal(String str) {
// code here
HashMap<Character,Integer>hm=new HashMap<>();
hm.put('I',1);
hm.put('V',5);
hm.put('X',10);
hm.put('L',50);
hm.put('C',100);
hm.put('D',500);
hm.put('M',1000);

char arr[]=str.toCharArray();
int sum=0;
for(int i=0;i<arr.length-1;i++){
if(hm.get(arr[i])>=hm.get(arr[i+1])){
sum+=hm.get(arr[i]);
}else{
sum-=hm.get(arr[i]);
}
}
sum+=hm.get(arr[arr.length-1]);
return sum;
}
}```