🍑 OJ专栏

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🍑 HDOJ 1022 Train Problem Ⅰ

输入

3 123 321
3 123 312

输出

Yes.
in
in
in
out
out
out
FINISH
No.
FINISH

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🍑 思路

🍤 栈顶元素与目标元素不匹配就进栈，匹配就出栈
🍤 匹配完：yes  源序列全进栈，栈顶不能匹配：no

import java.util.*;

public class Main
{
	public static void main(String[] args)
	{
		Scanner sc = new Scanner(System.in);
		while (sc.hasNext())
		{
			int n = sc.nextInt();
			String s1 = sc.next();
			int i1 = 0;
			int i2 = 0;
			String s2 = sc.next();
			Stack<Character> stack = new Stack<>();
			ArrayList<String> list = new ArrayList<>();
			stack.add('#');// 哨兵（保证栈不空）
			while (!stack.isEmpty())
			{
				if (i2 == n)
					break;
				if (stack.peek() == s2.charAt(i2))
				{
					stack.pop();
					list.add("out");
					i2++;
				} else
				{
					if (i1 == n)
						break;
					stack.add(s1.charAt(i1++));
					list.add("in");
				}
			}
			if (i2 == n && stack.peek() == '#')
			{
				System.out.println("Yes.");
				for (int i = 0; i < list.size(); i++)
					System.out.println(list.get(i));
			} else
			{
				System.out.println("No.");
			}
			System.out.println("FINISH");
		}
	}
}