On Sat, Apr 9, 2016 at 8:18 AM, Joe <lildinh...@gmail.com> 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 -- https://mail.python.org/mailman/listinfo/python-list
