CLEANRBT  Cleaning Robot
Here, we want to solve path planning for a mobile robot cleaning a rectangular room floor with furniture.
Consider the room floor paved with square tiles whose size fits the cleaning robot (1 × 1). There are 'clean tiles' and 'dirty tiles', and the robot can change a 'dirty tile' to a 'clean tile' by visiting the tile. Also there may be some obstacles (furniture) whose size fits a tile in the room. If there is an obstacle on a tile, the robot cannot visit it. The robot moves to an adjacent tile with one move. The tile onto which the robot moves must be one of four tiles (i.e., east, west, north or south) adjacent to the tile where the robot is present. The robot may visit a tile twice or more.
Your task is to write a program which computes the minimum number of moves for the robot to change all 'dirty tiles' to 'clean tiles', if ever possible.
Input
IThe input consists of multiple maps, each representing the size and arrangement of the room. A map is given in the following format.
w h
c11 c12 c13 ... c1w
c21 c22 c23 ... c2w
...
ch1 ch2 ch3 ... chw
The integers w and h are the lengths of the two sides of the floor of the room in terms of widths of floor tiles. w and h are less than or equal to 20. The character cyx represents what is initially on the tile with coordinates (x, y) as follows.
'.' : a clean tile
'*' : a dirty tile
'x' : a piece of furniture (obstacle)
'o' : the robot (initial position)
In the map the number of 'dirty tiles' does not exceed 10. There is only one 'robot'.
The end of the input is indicated by a line containing two zeros.
Output
For each map, your program should output a line containing the minimum number of moves. If the map includes 'dirty tiles' which the robot cannot reach, your program should output 1.
Example
Input: 7 5 ....... .o...*. ....... .*...*. ....... 15 13 .......x....... ...o...x....*.. .......x....... .......x....... .......x....... ............... xxxxx.....xxxxx ............... .......x....... .......x....... .......x....... ..*....x....*.. .......x....... 10 10 .......... ..o....... .......... .......... .......... .....xxxxx .....x.... .....x.*.. .....x.... .....x.... 0 0 Output: 8 49 1
hide comments
fahad991:
20200528 09:50:42
Got AC ! Very nice problem.


may_007:
20200325 19:45:31
AC in one go 

emilio_cosy:
20191001 15:36:28
Could anybody explain why I exceeded the time limit? I used bit masking DP that is similiar to https://www.geeksforgeeks.org/bitmaskingdynamicprogrammingset2tsp/ 

ab_biswas09:
20190318 20:37:17
Finally AC , simple TSP with Bitmasking 

letuantam96:
20190312 10:24:19
Last edit: 20190312 10:50:24 

hieudoan7:
20190304 12:32:46
Finally, I got it.


vengatesh15:
20180123 13:56:09
AC in 1 go :) 

byndz1:
20171026 09:00:12
Could someone give me some testcases please. I am getting WA every single time and I dunno y :/ 

sas1905:
20170620 23:02:59
simple recursion 0.40 ..with dp 0.00 :) 

sonu:
20170604 22:53:06
no problem if you don't know tsp ,as it is normal dp+bitmask,and of course bfs 
Added by:  Camilo Andrés Varela León 
Date:  20070726 
Time limit:  0.609s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JSRHINO NODEJS PERL6 VB.NET 
Resource:  Japan Domestic, 2005 