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문제

원섭이와 상현이는 보드 게임을 구매했다. 게임판은 무한 이진 트리와 비슷한 형태이다. 게임판은 노드와 노드를 연결하는 양방향 도로로 이루어져 있다.

루트 노드는 게임판의 가장 위에 있고, 이 노드의 레벨은 0이다. 모든 노드는 항상 두 자식을 가지며, 왼쪽 자식과 오른쪽 자식이다. 왼쪽 자식의 위치는 부모 노드의 왼쪽 아래이고, 오른쪽 자식의 위치는 오른쪽 아래이다. 자식 노드의 레벨은 부모 노드의 레벨보다 1 크다.

도로는 부모 노드와 자식 노드를 연결하는 도로가 있고, 같은 레벨에 있는 노드를 모두 연결하는 도로가 있다. 같은 레벨에 있는 노드를 모두 연결하는 도로는 각 레벨의 가장 왼쪽 노드에서 시작하며, 각각의 노드와 그 오른쪽에 있는 노드를 연결한다.

한 노드에서 도로를 한 번 이용해서 다른 노드로 이동할 수 있다. 이동은 다음과 같이 총 5가지가 있으며, 한 글자로 나타낼 수 있다.

  • 왼쪽 자식으로 이동: 1
  • 오른쪽 자식으로 이동: 2
  • 부모 노드로 이동: U
  • 같은 레벨의 바로 왼쪽에 있는 노드로 이동: L
  • 같은 레벨의 바로 오른쪽에 있는 노드로 이동: R

위와 같은 이동의 연속을 경로라고 한다.

예를 들어, 루트 노드에서 '221LU'로 이동한다면, A가 적힌 노드로 이동할 수 있다.

게임판 위의 두 노드가 주어진다. 이때, 한 노드에서 다른 노드로 이동하는데 필요한 이동 횟수의 최솟값을 구하는 프로그램을 작상하시오. 두 노드는 루트에서 이동한 경로로 주어지며, 두 경로가 같은 노드인 경우에 답은 0이다.

입력

첫째 줄에 루트에서 첫 번째 노드로 이동하는 경로가 주어진다.

둘째 줄에 루트에서 두 번째 노드로 이동하는 경로가 주어진다.

두 경로의 길이는 100,000을 넘지 않으며, 항상 올바른 경로이다. (즉, 이동할 수 없는 상황은 나타나지 않는다)

출력

첫째 줄에 한 노드에서 다른 노드로 이동하는데 필요한 이동 횟수의 최솟값을 출력한다.

예제 입력 1

221LU
12L2

예제 출력 1

3

힌트

문제의 그림은 예제를 나타낸다.

[{"problem_id":"9283","problem_lang":"0","title":"\ubcf4\ub4dc \uac8c\uc784 \"\ud2b8\ub9ac\"","description":"<p>\uc6d0\uc12d\uc774\uc640 \uc0c1\ud604\uc774\ub294 \ubcf4\ub4dc \uac8c\uc784\uc744 \uad6c\ub9e4\ud588\ub2e4. \uac8c\uc784\ud310\uc740 \ubb34\ud55c \uc774\uc9c4 \ud2b8\ub9ac\uc640 \ube44\uc2b7\ud55c \ud615\ud0dc\uc774\ub2e4. \uac8c\uc784\ud310\uc740 \ub178\ub4dc\uc640 \ub178\ub4dc\ub97c \uc5f0\uacb0\ud558\ub294 \uc591\ubc29\ud5a5 \ub3c4\ub85c\ub85c \uc774\ub8e8\uc5b4\uc838 \uc788\ub2e4.<\/p>\r\n\r\n<p>\ub8e8\ud2b8 \ub178\ub4dc\ub294 \uac8c\uc784\ud310\uc758 \uac00\uc7a5 \uc704\uc5d0 \uc788\uace0, \uc774 \ub178\ub4dc\uc758 \ub808\ubca8\uc740 0\uc774\ub2e4. \ubaa8\ub4e0 \ub178\ub4dc\ub294 \ud56d\uc0c1 \ub450 \uc790\uc2dd\uc744 \uac00\uc9c0\uba70, \uc67c\ucabd \uc790\uc2dd\uacfc \uc624\ub978\ucabd \uc790\uc2dd\uc774\ub2e4. \uc67c\ucabd \uc790\uc2dd\uc758 \uc704\uce58\ub294 \ubd80\ubaa8 \ub178\ub4dc\uc758 \uc67c\ucabd \uc544\ub798\uc774\uace0, \uc624\ub978\ucabd \uc790\uc2dd\uc758 \uc704\uce58\ub294 \uc624\ub978\ucabd \uc544\ub798\uc774\ub2e4. \uc790\uc2dd \ub178\ub4dc\uc758 \ub808\ubca8\uc740 \ubd80\ubaa8 \ub178\ub4dc\uc758 \ub808\ubca8\ubcf4\ub2e4 1 \ud06c\ub2e4.<\/p>\r\n\r\n<p>\ub3c4\ub85c\ub294 \ubd80\ubaa8 \ub178\ub4dc\uc640 \uc790\uc2dd \ub178\ub4dc\ub97c \uc5f0\uacb0\ud558\ub294 \ub3c4\ub85c\uac00 \uc788\uace0, \uac19\uc740 \ub808\ubca8\uc5d0 \uc788\ub294 \ub178\ub4dc\ub97c \ubaa8\ub450 \uc5f0\uacb0\ud558\ub294 \ub3c4\ub85c\uac00 \uc788\ub2e4. \uac19\uc740 \ub808\ubca8\uc5d0 \uc788\ub294 \ub178\ub4dc\ub97c \ubaa8\ub450 \uc5f0\uacb0\ud558\ub294 \ub3c4\ub85c\ub294 \uac01 \ub808\ubca8\uc758 \uac00\uc7a5 \uc67c\ucabd \ub178\ub4dc\uc5d0\uc11c \uc2dc\uc791\ud558\uba70, \uac01\uac01\uc758 \ub178\ub4dc\uc640 \uadf8 \uc624\ub978\ucabd\uc5d0 \uc788\ub294 \ub178\ub4dc\ub97c \uc5f0\uacb0\ud55c\ub2e4.<\/p>\r\n\r\n<p><img alt=\"\" src=\"\/upload\/images\/treegame.png\" style=\"height:262px; width:461px\" \/><\/p>\r\n\r\n<p>\ud55c \ub178\ub4dc\uc5d0\uc11c \ub3c4\ub85c\ub97c \ud55c \ubc88 \uc774\uc6a9\ud574\uc11c \ub2e4\ub978 \ub178\ub4dc\ub85c \uc774\ub3d9\ud560 \uc218 \uc788\ub2e4. \uc774\ub3d9\uc740 \ub2e4\uc74c\uacfc \uac19\uc774 \ucd1d 5\uac00\uc9c0\uac00 \uc788\uc73c\uba70, \ud55c \uae00\uc790\ub85c \ub098\ud0c0\ub0bc \uc218 \uc788\ub2e4.<\/p>\r\n\r\n<ul>\r\n\t<li>\uc67c\ucabd \uc790\uc2dd\uc73c\ub85c \uc774\ub3d9: 1<\/li>\r\n\t<li>\uc624\ub978\ucabd \uc790\uc2dd\uc73c\ub85c \uc774\ub3d9: 2<\/li>\r\n\t<li>\ubd80\ubaa8 \ub178\ub4dc\ub85c \uc774\ub3d9: U<\/li>\r\n\t<li>\uac19\uc740 \ub808\ubca8\uc758 \ubc14\ub85c \uc67c\ucabd\uc5d0 \uc788\ub294 \ub178\ub4dc\ub85c \uc774\ub3d9: L<\/li>\r\n\t<li>\uac19\uc740 \ub808\ubca8\uc758 \ubc14\ub85c \uc624\ub978\ucabd\uc5d0 \uc788\ub294 \ub178\ub4dc\ub85c \uc774\ub3d9: R<\/li>\r\n<\/ul>\r\n\r\n<p>\uc704\uc640 \uac19\uc740 \uc774\ub3d9\uc758 \uc5f0\uc18d\uc744 \uacbd\ub85c\ub77c\uace0 \ud55c\ub2e4.<\/p>\r\n\r\n<p>\uc608\ub97c \ub4e4\uc5b4, \ub8e8\ud2b8 \ub178\ub4dc\uc5d0\uc11c &#39;221LU&#39;\ub85c \uc774\ub3d9\ud55c\ub2e4\uba74, A\uac00 \uc801\ud78c \ub178\ub4dc\ub85c \uc774\ub3d9\ud560 \uc218 \uc788\ub2e4.<\/p>\r\n\r\n<p>\uac8c\uc784\ud310 \uc704\uc758 \ub450 \ub178\ub4dc\uac00 \uc8fc\uc5b4\uc9c4\ub2e4. \uc774\ub54c, \ud55c \ub178\ub4dc\uc5d0\uc11c \ub2e4\ub978 \ub178\ub4dc\ub85c \uc774\ub3d9\ud558\ub294\ub370 \ud544\uc694\ud55c \uc774\ub3d9 \ud69f\uc218\uc758 \ucd5c\uc19f\uac12\uc744 \uad6c\ud558\ub294 \ud504\ub85c\uadf8\ub7a8\uc744 \uc791\uc0c1\ud558\uc2dc\uc624. \ub450 \ub178\ub4dc\ub294 \ub8e8\ud2b8\uc5d0\uc11c \uc774\ub3d9\ud55c \uacbd\ub85c\ub85c \uc8fc\uc5b4\uc9c0\uba70, \ub450 \uacbd\ub85c\uac00 \uac19\uc740 \ub178\ub4dc\uc778 \uacbd\uc6b0\uc5d0 \ub2f5\uc740 0\uc774\ub2e4.<\/p>\r\n","input":"<p>\uccab\uc9f8 \uc904\uc5d0 \ub8e8\ud2b8\uc5d0\uc11c \uccab \ubc88\uc9f8 \ub178\ub4dc\ub85c \uc774\ub3d9\ud558\ub294 \uacbd\ub85c\uac00 \uc8fc\uc5b4\uc9c4\ub2e4.<\/p>\r\n\r\n<p>\ub458\uc9f8 \uc904\uc5d0 \ub8e8\ud2b8\uc5d0\uc11c \ub450 \ubc88\uc9f8 \ub178\ub4dc\ub85c \uc774\ub3d9\ud558\ub294 \uacbd\ub85c\uac00 \uc8fc\uc5b4\uc9c4\ub2e4.<\/p>\r\n\r\n<p>\ub450 \uacbd\ub85c\uc758 \uae38\uc774\ub294 100,000\uc744 \ub118\uc9c0 \uc54a\uc73c\uba70, \ud56d\uc0c1 \uc62c\ubc14\ub978 \uacbd\ub85c\uc774\ub2e4. (\uc989, \uc774\ub3d9\ud560 \uc218 \uc5c6\ub294 \uc0c1\ud669\uc740 \ub098\ud0c0\ub098\uc9c0 \uc54a\ub294\ub2e4)<\/p>\r\n","output":"<p>\uccab\uc9f8 \uc904\uc5d0 \ud55c \ub178\ub4dc\uc5d0\uc11c \ub2e4\ub978 \ub178\ub4dc\ub85c \uc774\ub3d9\ud558\ub294\ub370 \ud544\uc694\ud55c \uc774\ub3d9 \ud69f\uc218\uc758 \ucd5c\uc19f\uac12\uc744 \ucd9c\ub825\ud55c\ub2e4.<\/p>\r\n","hint":"<p>\ubb38\uc81c\uc758 \uadf8\ub9bc\uc740 \uc608\uc81c\ub97c \ub098\ud0c0\ub0b8\ub2e4.<\/p>\r\n","original":"0","html_title":"0","problem_lang_tcode":"Korean"},{"problem_id":"9283","problem_lang":"1","title":"Board","description":"<p>Mirko and Slavko have a new board game. The game board resembles a complete infinite binary tree. More precisely, the board consists of nodes and two-way roads connecting them. The root node is located at the top of the board and we say it is at level zero. Each node has exactly two children, the left child and the right child, located in the lower-left and the lower-right directions of the parent node. The level of a child node is one greater than the level of the parent node. In addition to roads connecting a parent node with its children, there are roads connecting all of the nodes at a particular level &ndash; for each level, starting from the leftmost node, there is a road connecting each node to the next node to the right on the same level.<\/p>\r\n\r\n<p><img alt=\"\" src=\"\/upload\/images\/treegame.png\" style=\"height:262px; width:461px\" \/><\/p>\r\n\r\n<p>Each path through the game board is a sequence of steps, each moving from a node to a different node via a single road. Each step can be described by a single character as follows:<\/p>\r\n\r\n<ul>\r\n\t<li>character &quot;1&quot; describes moving from a node to its left child,<\/li>\r\n\t<li>character &quot;2&quot; describes moving from a node to its right child,<\/li>\r\n\t<li>character &quot;U&quot; describes moving from a node to its parent,<\/li>\r\n\t<li>character &quot;L&quot; describes moving from a node to the next node to the left on the same level,<\/li>\r\n\t<li>character &quot;R&quot; describes moving from a node to the next node to the right on the same level.<\/li>\r\n<\/ul>\r\n\r\n<p>For example, if we were to start at the root node and take the sequence of steps &quot;221LU&quot; we would end up in the node denoted with the letter &bdquo;A\u201f in the figure above.<\/p>\r\n\r\n<p>Write a program that will, given two nodes on the board, find the smallest number of steps needed to go from one node to the other. The two nodes are given by specifying paths from the root node to them. If the two paths lead to the same node, the answer is zero.<\/p>\r\n","input":"<p>The first line of input contains a sequence of at most 100 000 characters &ndash; the path from the root to the first node.<\/p>\r\n\r\n<p>The second line of input contains a sequence of at most 100 000 characters &ndash; the path from the root to the second node.<\/p>\r\n\r\n<p>The two paths will be valid (it will be possible to make every move in both sequences).<\/p>\r\n","output":"<p>The first and only line of output should contain a single integer - the smallest number of steps needed to go from one node to the other.<\/p>\r\n","hint":"","original":"1","html_title":"0","problem_lang_tcode":"English"}]

출처

Olympiad > Central European Olympiad in Informatics > CEOI 2013 > Day 2 4번