https://www.geeksforgeeks.org/problems/convert-to-roman-no/1


//User function template for JAVA

class Solution
{
	String convertToRoman(int n) {
		//code here
		String[] romanNumerals={"M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"};
		int  values[]={1000,900,500,400,100,90,50,40,10,9,5,4,1};
		
		String s="";
		for(int i=0;i<values.length;i++){
		    while(n>=values[i]){
		        n=n-values[i];
		        s=s+romanNumerals[i];
		    }
		}
		return s;
	}
}
==============================================================

//{ Driver Code Starts
// Initial Template for Java

import java.io.*;
import java.util.*;

class GFG {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int tc = Integer.parseInt(br.readLine().trim());
        while (tc-- > 0) {
            String s = br.readLine().trim();
            Solution ob = new Solution();
            System.out.println(ob.romanToDecimal(s));

            System.out.println("~");
        }
    }
}
// } Driver Code Ends


// User function Template for Java

class Solution {
    // Finds decimal value of a given roman numeral
    public int romanToDecimal(String s) {
        // code here
        Map<Character,Integer> roman=new HashMap<>();
        roman.put('I',1);
        roman.put('V',5);
        roman.put('X',10);
        roman.put('L',50);
         roman.put('C',100);
          roman.put('D',500);
          roman.put('M',1000);
          
          int result=0;
          for(int i=0;i<s.length();i++){
              int curr=roman.get(s.charAt(i));
              if(i+1<s.length() && roman.get(s.charAt(i+1))>curr){
                  result=result-curr;
              }else{
                  result=result+curr;
              }
          }
          return result;
        
    }
}
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