猿辅导笔试7.31第二题

//
//修改过后
import java.util.Scanner;
import java.util.Stack;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String boxs = sc.nextLine();
        int n = boxs.length();
        int ret = 0;
        Stack<Integer> c = new Stack<Integer> ();
        c.push(0);
        for (int i = 0; i < n; ++i) {
            // System.out.println(c.toString());
            char ch = boxs.charAt(i);
            if (ch == '[') {
                c.push(1);
            } else if (ch == ']') {
                if (i < n-1 && (Character.isDigit(boxs.charAt(i+1)))) {
                    c.push(c.pop() * (boxs.charAt(i+1) - '0'));
                    i = i+1;
                }
                c.push(c.pop() + c.pop());
            }
        }
        while(!c.empty())
            ret += c.pop();
        System.out.println(ret);
    }
}
// 原不正确代码：






import java.util.Scanner;
import java.util.Stack;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String boxs = sc.nextLine();
        int n = boxs.length();
        int ret = 0;
        Stack<Integer> c = new Stack<Integer> ();
        Stack<Character> s = new Stack<> ();
        c.push(0);
        s.push(boxs.charAt(0));
        for (int i = 1; i < n; ++i) {
            // System.out.println(c.toString());
            char ch = boxs.charAt(i);
            if (ch == '[') {
                if ( !s.empty() && s.peek() == ']') {
                    s.pop();
                    s.pop();
                    if (!c.empty()) {
                        if (c.peek().equals(0)) {
                            c.pop();
                            c.push(1);
                        } else {
                            int sum = 0;
                            int e;
                            while (c.peek() != 0) {
                                e = c.pop();
                                sum += e;
                            }
                            c.pop();
                            c.push(sum + 1);
                        }
                    }
                }
                c.push(0);
                s.push(ch);
            } else if (ch == ']') {
                s.push(ch);
            } else {
                if ( !s.empty()) {
                    s.pop();
                    s.pop();
                    if (!c.empty()) {
                        if (c.peek().equals(0)) {
                            c.pop();
                            c.push(ch - '0');
                        } else {
                            int sum = 0;
                            int e;
                            while (c.peek() != 0) {
                                e = c.pop();
                                sum += e;
                            }
                            
                            c.pop();
                            c.push((sum+1)* (ch - '0'));
                        }
                    }
                }
            }
        }
        while(!c.empty())
             ret += c.pop();
        System.out.println(ret);
    }
}