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

[Mark Lawrence]

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