Method countRev

CountTheReversals.java:3–21

(String s)

class Sol
{
    int countRev (String s)
    {
        // your code here  
        if(s.length()%2!=0) return -1;
        
        int open=0,close=0,rev=0;
        
        for(int i=0;i<s.length();i++)
        {
            if(s.charAt(i)=='{') open++;
            else
            {
                if(open==0) close++;
                else open--;
            }
        }
        rev=(int)(Math.ceil(open/2.0) + Math.ceil(close/2.0)); 
        return rev;
    }
}