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

Newsgroups comp.lang.python
Date 2016-04-09 12:41 -0700
References (1 earlier) <CALwzidkhCO0bK2XxP-BZ=aPxuSX-ZiSxq_Yn7pe+ehV8qTsN8Q@mail.gmail.com> <mailman.129.1460220245.2253.python-list@python.org> <e42777b0-fc2b-4f2c-8c2b-a53b41bfe3f7@googlegroups.com> <nebkro$8j2$1@ger.gmane.org> <mailman.137.1460229825.2253.python-list@python.org>
Message-ID <4bdfe218-11a6-4866-b1c3-e3a2e0661e47@googlegroups.com> (permalink)
Subject Re: Find the number of robots needed to walk through the rectangular grid
From Joe <lildinho14@gmail.com>

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On Saturday, 9 April 2016 21:24:02 UTC+2, Mark Lawrence  wrote:
> 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

Sorry, I was desperate 
I deleted the post

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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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