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Re: Find the number of robots needed to walk through the rectangular grid

Path csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail
From Mark Lawrence <breamoreboy@yahoo.co.uk>
Newsgroups comp.lang.python
Subject Re: Find the number of robots needed to walk through the rectangular grid
Date Sat, 9 Apr 2016 20:23:28 +0100
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On 09/04/2016 18:13, Joe wrote:
> On Saturday, 9 April 2016 18:44:20 UTC+2, Ian  wrote:
>> On Sat, Apr 9, 2016 at 8:18 AM, Joe  wrote:
>>> How to find the number of robots needed to walk through the rectangular grid
>>> The movement of a robot in the field is divided into successive steps
>>>
>>> In one step a robot can move either horizontally or vertically (in one row or in one column of cells) by some number of cells
>>>
>>> A robot can move in one step from cell X to cell Y if and only if the distance between the centers of the cells X and Y is equal to the sum of integers contained in X and Y
>>>
>>> Cell X is reachable for robot A if either A is currently standing in the cell X or A can reach X after some number of steps. During the transfer the robot can choose the direction (horizontal or vertical) of each step arbitrarily
>>> [![enter image description here][1]][1]
>>>
>>> I started implementing it by first checking the row and print the index of the Cell X and Y where the distance is equal to the sum of integers contained in X and Y
>>>
>>> but after coding I found it difficult to remember the index when moving vertically
>>>
>>>   So I thought to Build a graph where nodes are grid cells and edges are legal direct movements, then run any connected components algorithm to find which cells are reachable from each other
>>>
>>>
>>> Can anyone implement it with graphs or queue?
>>
>> I'd use a disjoint-set data structure. The number of robots needed is
>> equal to the number of disjoint subsets.
>>
>> https://en.wikipedia.org/wiki/Disjoint-set_data_structure
>
> Could you post a formal solution of disjoint-set using my algorithm
>

You write the code, we comment on it.  No code, no comment.  Got the 
message?

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence

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Thread

Find the number of robots needed to walk through the rectangular grid Joe <lildinho14@gmail.com> - 2016-04-09 07:18 -0700
  Re: Find the number of robots needed to walk through the rectangular grid Ian Kelly <ian.g.kelly@gmail.com> - 2016-04-09 10:43 -0600
    Re: Find the number of robots needed to walk through the rectangular grid Joe <lildinho14@gmail.com> - 2016-04-09 10:13 -0700
      Re: Find the number of robots needed to walk through the rectangular grid Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-04-09 15:10 -0400
      Re: Find the number of robots needed to walk through the rectangular grid Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-04-09 20:23 +0100
        Re: Find the number of robots needed to walk through the rectangular grid Joe <lildinho14@gmail.com> - 2016-04-09 12:41 -0700
          Re: Find the number of robots needed to walk through the rectangular grid Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-04-09 20:55 +0100
            Re: Find the number of robots needed to walk through the rectangular grid Joe <lildinho14@gmail.com> - 2016-04-09 14:28 -0700

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