Online JudgeProblem SetAuthorsOnline ContestsUser
Web Board
Home Page
Statistical Charts
Submit Problem
Online Status
Update your info
Authors ranklist
Current Contest
Past Contests
Scheduled Contests
Award Contest
User ID:
Harder Sokoban Problem
Time Limit: 1000MSMemory Limit: 65536K
Total Submissions: 923Accepted: 389


The game of sokoban is played in a rectangular labirinth of N by N cells with each cell either empty, denoted by '.' character (ASCII 46), or occupied by wall, denoted by '#' character (ASCII 35). There is also a single destination cell, denoted by '*' character (ASCII 42).

One player and one container are located in the empty cells of the labirinth. The player can move between the empty cells in horizontal or vertical direction. If the cell where the player tries to move is occupied by container, the container is "pushed" to the next cell in the same direction. That next cell must, of course, be empty.

The objective of the game is well-known: to place the container in the destination cell with the minimum number of moves. Your task, however, is different: given the field, select starting position for the player and the container so as to maximize the required number of moves.


First line of input contains number N -- the field size. The following N lines consist of N characters each -- representation the field. The input field always contains at least one empty cell adjacent to the destination cell.
2 ≤ N ≤ 25


Output must contain a single integer -- the maximal number of moves.

Sample Input


Sample Output



Northeastern Europe 2004, Far-Eastern Subregion

[Submit]   [Go Back]   [Status]   [Discuss]

Home Page   Go Back  To top

All Rights Reserved 2003-2013 Ying Fuchen,Xu Pengcheng,Xie Di
Any problem, Please Contact Administrator