ValidParantheses.java

class ValidParantheses {
    public boolean isValid(String s) {
        Stack<Character> stack = new Stack<>();
        for(char c : s.toCharArray()){
            if(c == '{' || c == '[' || c == '('){
                stack.push(c);
            }else{
                if(stack.isEmpty()){
                    return false;
                }else{
                    char top = stack.peek();
                    if(c == '}' && top == '{' ||
                      c == ')' && top =='(' ||
                      c == ']' && top == '['){
                        stack.pop();
                    }else{
                        return false;
                    }
                }
            }
        }
        return stack.isEmpty();
    }
    
    public static void main(String[] args) {
        System.out.println(isValid("()[]{}"));
    }
}