题解 | #好串#

遇到a入栈，遇到b出栈，判断最后栈是否为空就行。

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String str = sc.nextLine();
        Stack<Character> s = new Stack<Character>();
        char []charArray = str.toCharArray();
        boolean b = true;
        for(int i = 0 ;i<charArray.length;i++){
            if(charArray[i]=='a'){
                s.add('a');
            }else if(s.isEmpty()){
                b = false;
                break;
            }else{
                s.pop();
            }
        }
        if(b){
            if(s.isEmpty()) System.out.println("Good");
            else System.out.println("Bad");
        }else{
            System.out.println("Bad");
        }
    }
}