DuplicateParanthesis.java

import java.util.*;
public class DuplicateParanthesis {
    public static boolean isOperator(char ch){
        return ch=='+' || ch=='-' || ch=='*' || ch=='/';
    }
    public static boolean duplicateParanthesis(String str){
        Stack<Character> s = new Stack<>();
        for(int i=0;i<str.length();i++){
            char ch = str.charAt(i);
            if (Character.isLetter(ch)||ch=='('||isOperator(ch)){
                s.push(ch);
            }else{
                int count=0;
                while(s.peek()!='('){
                    count++;
                    s.pop();
                }
                if (count<1){
                    return true;
                }
                s.pop();
            }
        }
        return false;
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter the string: ");
        String str = sc.nextLine();
        System.out.println(duplicateParanthesis(str));
    }
}