Convert_Roman_Number_To_Integer

#include<bits/stdc++.h>
using namespace std;

int romanToDecimal(string &str)
{
    int Soln=0;
    unordered_map<char,int>nums;
    
    nums['I']=1;
    nums['V']=5;
    nums['X']=10;
    nums['L']=50;
    nums['C']=100;
    nums['D']=500;
    nums['M']=1000;
    
    for(int i=str.size()-1; i>=0; i--)
    {
        if(i<str.size()-1 && nums[str[i]]<nums[str[i+1]])
            Soln-=nums[str[i]];
        else
            Soln+=nums[str[i]];
    }
    return Soln;
   }
};