Update Minimum Bracket Reversal

Author: akshayavb99

Course 2 - Data Structures in JAVA/Lecture 9 - Stacks/Minimum Bracket Reversal

@@ -31,3 +31,57 @@ Sample Input 2:
 Sample Output 2:
 1
 */
+import java.util.*;
+public class Solution {
+
+	public static int countBracketReversals(String input) {
+		//Your code goes here
+        if (input.length()%2!=0)
+        {
+            return -1;
+        }
+        Stack<Character> stack=new Stack<Character>();
+        int count=0;
+        for (int i=0;i<input.length();i++)
+        {
+            char c=input.charAt(i);
+            if (c=='{')
+            {
+                stack.push(c);
+            }
+            else
+            {
+                if (stack.isEmpty())
+                {
+                    stack.push(c);
+                }
+                else if (stack.peek()=='}')
+                {
+                    stack.push(c);
+                }
+                else if (stack.peek()=='{')
+                {
+                    stack.pop();
+                }
+            }
+        }
+        
+        while(!stack.isEmpty())
+        {
+            char c1=stack.pop();
+            char c2=stack.pop();
+            
+            if (c1==c2)
+            {
+                count=count+1;
+            }
+            else
+            {
+                count=count+2;
+            }
+        }
+        return count;
+        
+	}
+
+}