Add Roman To Integer conversion

Author: pandeyarun709

Conversions/RomanToInteger.java

@@ -0,0 +1,60 @@
+import java.util.*;
+public class RomanToInteger {
+		
+		/*
+		   This function convert Roman number into Integer
+		   @param A is Roman number string 
+		*/
+	    public static int romanToInt(String A) {
+	        Map<Character , Integer> map = new HashMap<>();
+	        map.put('I' , 1);
+	        map.put('V' , 5);
+	        map.put('X' , 10);
+	        map.put('L' , 50);
+	        map.put('C' , 100);
+	        map.put('D' , 500);
+	        map.put('M' , 1000);
+	        
+	        char c = A.charAt(A.length()-1);
+	        char prev = ' ';
+	        
+	        int sum =0;
+	       
+	        int newPrev = 0, currentNum =0;
+	        for(int i = A.length() -1;i>=0;i--)
+	        {
+	            c = A.charAt(i);
+	            
+	            
+	            if(prev != ' ') {
+	            	//checking current Number greater then previous or not
+	                newPrev = map.get(prev) > newPrev ? map.get(prev) : newPrev ; 
+	            }
+	               
+	             
+	             currentNum = map.get(c);  
+	               
+	             if(currentNum >= newPrev ) //if current number greater then prev max previous then add
+	            {
+	                    sum += currentNum;
+	            } 
+	            else {
+	            
+	                sum -= currentNum;  // subtract upcoming number until upcoming number not greater then prev max
+	            }     
+	             
+	          prev = c;    
+	        }
+	        
+	        return sum;
+    }
+
+
+	public static void main(String[] args) {
+	
+		
+		int sum = romanToInt("MDCCCIV") ;
+		System.out.println(sum);
+	}
+
+}