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문제

모범생 현수는 코딩하는 시간을 늘리기 위해 타임 머신을 구매 했다. 현수는 정상적으로 문제를 코딩하거나 (타임 머신을 사용하지 않고), 과거의 임의의 지점으로 시간여행 할 수 있다.  미래로 시간 여행 할 수 없으며, 과거로 가면 새로운 미래가 진행된다.

현수는 자유롭게 문제를 풀거나 과거로 돌아가면서 자신이 푼 문제 목록을 기록한다. 과거로 돌아가면 과거 이전까지 풀었던 문제 목록만 남는다.

현수는  기록 되어 있는 문제 목록 중 가장 최근에 푼 문제 번호를 알고 싶다. (가장 최근에 푼 문제가 없다면 -1을 출력)

매 쿼리마다 문제 목록에 기록되어 있는 가장 최근에 푼 문제를 출력하는 프로그램을 작성하시오.

현수는 개인의 타임라인 관점에서 연속적인 업데이트를 나타내는  N (1 <= N <= 80,000) 개의 쿼리 Qi(1...N) 를 제공한다.

각 쿼리는 한 줄의 입력이다. 각 줄은 하나의 문자 c ( 'a', 's', 't' 중 하나)로 시작한다. c가 'a'또는 't' 이면 c 다음에 공백과 정수 K가 주어진다. (1 <= K <= 1,000,000)

c가 'a' 이면 현수는 문제 번호가 K인 문제를 풀고 문제 목록에 기록 한다.

c가 's' 이면 현수는 가장 최근에 작성한 문제 목록을 삭제한다.

c가 't'이면, 현수는 K 번째 쿼리 직전까지 시간을 거슬러 올라 간다. 즉, 현수는 K-1번째 쿼리와 K번째 쿼리 사이로 시간 여행한다. (입력을 위해 예제 입력 참조). K 쿼리  바로 전에 있던 푼 문제 목록으로 되돌아 간다.

이해를 돕기 위해 아래에 푼 문제 목록과 12개의 쿼리, 각 쿼리에 대한 출력결과가 주어진다.  

Q#   쿼리     문제목록      출력         참조
 1   a 5  -> [5]         => 5        5번 문제를 목록에 기록
 2   a 3  -> [5,3]       => 3        3번 문제를  목록에 기록
 3   a 7  -> [5,3,7]     => 7        7번 문제를 목록에 기록
 4   s    -> [5,3]       => 3        가장 최근 기록한 7를 목록에서 삭제
 5   t 2  -> [5]         => 5        2번째 쿼리 직전으로 되돌아감
 6   a 2  -> [5,2]       => 2        2번 문제를 목록에 기록
 7   t 4  -> [5,3,7]     => 7        4번째 쿼리 직전으로 되돌아감
 8   a 4  -> [5,3,7,4]   => 4        4번 문제를 목록에 기록
 9   s    -> [5,3,7]     => 7        가장 최근 기록한 4를 목록에서 삭제
10   t 7  -> [5,2]       => 2        7번째 쿼리 직전으로 되돌아감
11   s    -> [5]         => 5        가장 최근 기록한 2를 목록에서 삭제
12   s    -> []          => -1       가장 최근 기록한 5를 목록에서 삭제

입력

첫 번째 줄 : 하나의 정수 N

두 번째 줄 부터 N+1번째 줄까지: 쿼리 Qi 

출력

1부터 N번째 줄 : Qi 처리 후 목록에 기록 되어 있는 가장 최근에 푼 문제를 출력하시오 (가장 최근에 푼 문제가 없으면 -1).

예제 입력 1

12
a 5
a 3
a 7
s
t 2
a 2
t 4
a 4
s
t 7
s
s

예제 출력 1

5
3
7
3
5
2
7
4
7
2
5
-1
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(\uc785\ub825\uc744 \uc704\ud574 \uc608\uc81c \uc785\ub825 \ucc38\uc870). K \ucffc\ub9ac&nbsp; \ubc14\ub85c \uc804\uc5d0 \uc788\ub358 \ud47c \ubb38\uc81c \ubaa9\ub85d\uc73c\ub85c \ub418\ub3cc\uc544 \uac04\ub2e4.<\/p>\r\n\r\n<p>\uc774\ud574\ub97c \ub3d5\uae30 \uc704\ud574 \uc544\ub798\uc5d0&nbsp;\ud47c \ubb38\uc81c \ubaa9\ub85d\uacfc 12\uac1c\uc758&nbsp;\ucffc\ub9ac,&nbsp;\uac01 \ucffc\ub9ac\uc5d0 \ub300\ud55c&nbsp;\ucd9c\ub825\uacb0\uacfc\uac00 \uc8fc\uc5b4\uc9c4\ub2e4.&nbsp;&nbsp;<\/p>\r\n\r\n<pre>\r\nQ#   \ucffc\ub9ac     \ubb38\uc81c\ubaa9\ub85d      \ucd9c\ub825         \ucc38\uc870\r\n 1   a 5  -&gt; [5]         =&gt; 5        5\ubc88 \ubb38\uc81c\ub97c \ubaa9\ub85d\uc5d0 \uae30\ub85d\r\n 2   a 3  -&gt; [5,3]       =&gt; 3        3\ubc88 \ubb38\uc81c\ub97c  \ubaa9\ub85d\uc5d0 \uae30\ub85d\r\n 3   a 7  -&gt; [5,3,7]     =&gt; 7        7\ubc88 \ubb38\uc81c\ub97c \ubaa9\ub85d\uc5d0 \uae30\ub85d\r\n 4   s    -&gt; [5,3]       =&gt; 3        \uac00\uc7a5 \ucd5c\uadfc \uae30\ub85d\ud55c 7\ub97c \ubaa9\ub85d\uc5d0\uc11c \uc0ad\uc81c\r\n 5   t 2  -&gt; [5]         =&gt; 5        2\ubc88\uc9f8 \ucffc\ub9ac \uc9c1\uc804\uc73c\ub85c \ub418\ub3cc\uc544\uac10\r\n 6   a 2  -&gt; [5,2]       =&gt; 2        2\ubc88 \ubb38\uc81c\ub97c \ubaa9\ub85d\uc5d0 \uae30\ub85d\r\n 7   t 4  -&gt; [5,3,7]     =&gt; 7        4\ubc88\uc9f8 \ucffc\ub9ac \uc9c1\uc804\uc73c\ub85c \ub418\ub3cc\uc544\uac10\r\n 8   a 4  -&gt; [5,3,7,4]   =&gt; 4        4\ubc88 \ubb38\uc81c\ub97c \ubaa9\ub85d\uc5d0 \uae30\ub85d\r\n 9   s    -&gt; [5,3,7]     =&gt; 7        \uac00\uc7a5 \ucd5c\uadfc \uae30\ub85d\ud55c 4\ub97c \ubaa9\ub85d\uc5d0\uc11c \uc0ad\uc81c\r\n10   t 7  -&gt; [5,2]       =&gt; 2        7\ubc88\uc9f8 \ucffc\ub9ac \uc9c1\uc804\uc73c\ub85c \ub418\ub3cc\uc544\uac10\r\n11   s    -&gt; [5]         =&gt; 5        \uac00\uc7a5 \ucd5c\uadfc \uae30\ub85d\ud55c 2\ub97c \ubaa9\ub85d\uc5d0\uc11c \uc0ad\uc81c\r\n12   s    -&gt; []          =&gt; -1       \uac00\uc7a5 \ucd5c\uadfc \uae30\ub85d\ud55c 5\ub97c \ubaa9\ub85d\uc5d0\uc11c \uc0ad\uc81c<\/pre>\r\n","input":"<p>\uccab \ubc88\uc9f8 \uc904 : \ud558\ub098\uc758 \uc815\uc218 N<\/p>\r\n\r\n<p>\ub450 \ubc88\uc9f8 \uc904 \ubd80\ud130 N+1\ubc88\uc9f8 \uc904\uae4c\uc9c0: \ucffc\ub9ac Q<sub>i<\/sub>&nbsp;<\/p>\r\n","output":"<p>1\ubd80\ud130 N\ubc88\uc9f8 \uc904 : Q<sub>i<\/sub> \ucc98\ub9ac \ud6c4 \ubaa9\ub85d\uc5d0 \uae30\ub85d \ub418\uc5b4 \uc788\ub294 \uac00\uc7a5 \ucd5c\uadfc\uc5d0 \ud47c \ubb38\uc81c\ub97c \ucd9c\ub825\ud558\uc2dc\uc624 (\uac00\uc7a5 \ucd5c\uadfc\uc5d0 \ud47c \ubb38\uc81c\uac00 \uc5c6\uc73c\uba74 -1).<\/p>\r\n","hint":"","original":"0","html_title":"0","problem_lang_tcode":"Korean"},{"problem_id":"6051","problem_lang":"1","title":"Time Travel","description":"<p>Farmer John has purchased an Acme Time Machine. He can now travel forward in time normally (without using the machine) or else jump back to an arbitrary point in the past, at which point time will start to go forward again, but potentially with events unfolding in a new, different way. FJ can never travel forward in time in his time machine.<\/p>\r\n\r\n<p>FJ wants to raise the best possible cow herd, so he is going to try several different ideas, keeping track of various statistics of his cow herd through different possible time and event paths.<\/p>\r\n\r\n<p>One statistic FJ cares about is the ID number of the cow he has had for the shortest period of time. Please help him out by writing a program to keep track of his herd and, after each command, reporting the ID of the most recently acquired cow of the cows he owns (or -1 if he has no cows).<\/p>\r\n\r\n<p>FJ has a set of N (1 &lt;= N &lt;= 80,000) queries Q_i, conveniently numbered 1..N, which represent consecutive updates from the point of view of FJ&#39;s personal timeline.<\/p>\r\n\r\n<p>Each query is a single line of input. The line begins with a single character c (one of &#39;a&#39;, &#39;s&#39;, or &#39;t&#39;). 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Revert to the herd that was present just before query K.<\/p>\r\n\r\n<p>By way of example, consider a series of 12 queries, shown below along with the cow name list and the resulting output for each query.<\/p>\r\n\r\n<pre>\r\n    Q#   Query   Owned Cows    Output      Comments\r\n     1   a 5  -&gt; [5]        =&gt; 5        Add a new cow with ID 5\r\n     2   a 3  -&gt; [5,3]      =&gt; 3        Add a new cow with ID 3\r\n     3   a 7  -&gt; [5,3,7]    =&gt; 7        Add a new cow with ID 7\r\n     4   s    -&gt; [5,3]      =&gt; 3        Sell recent cow 7\r\n     5   t 2  -&gt; [5]        =&gt; 5        Revert time to before query 2\r\n     6   a 2  -&gt; [5,2]      =&gt; 2        Add a new cow with ID 2\r\n     7   t 4  -&gt; [5,3,7]    =&gt; 7        Revert time to before query 4\r\n     8   a 4  -&gt; [5,3,7,4]  =&gt; 4        Add a new cow with ID 4\r\n     9   s    -&gt; [5,3,7]    =&gt; 7        Sell recent cow 4\r\n    10   t 7  -&gt; [5,2]      =&gt; 2        Revert time to before query 7\r\n    11   s    -&gt; [5]        =&gt; 5        Sell recent cow 2\r\n    12   s    -&gt; []         =&gt; -1       Sell recent cow 5<\/pre>\r\n","input":"<ul>\r\n\t<li>Line 1: A single integer: N<\/li>\r\n\t<li>Lines 2..N+1: Line i+1: query Q_i<\/li>\r\n<\/ul>\r\n","output":"<ul>\r\n\t<li>Lines 1..N: Line i: The ID of the most recently purchased cow after query i takes effect (-1 if no cows are owned).<\/li>\r\n<\/ul>\r\n","hint":"","original":"1","html_title":"0","problem_lang_tcode":"English"}]

출처

Olympiad > USA Computing Olympiad > 2009-2010 Season > USACO US Open 2010 Contest > Silver 3번