%Copyright 2006, Adarsh Krishnamurthy (me.berkeley.edu/~adarsh) and Athulan Vijayaraghavan (me.berkeley.edu/~athulan)

clc; clear all;
%first attempt using kruskal

%size of the maze - only square
maze_size = 10;

n_cells = maze_size*maze_size;

%listing all the cells with a uid in an array
k = 1;
for i = 1:maze_size
    for j = 1:maze_size
        corners = corner_pts([j i])';
        cells(k, :) = [k k corners(:)'];
        k = k + 1;    
    end
end
cells_master = cells;

%listing all the edges with a uid in an array
edges = [];
k = 1;
for i = 1:maze_size-1
    for j = 1:maze_size
        edges(k, :) = [k i j-1 i j];
        edges(k+1, :) = [k+1 j-1 i j i];
        k = k + 2;
    end
end
edges_master = edges;
edges_display = [edges; 0 0 0 0 maze_size; 0 0 maze_size maze_size maze_size; 0 maze_size maze_size maze_size 0; 0 maze_size 0 0 0];

ctr = 1;
tic
while max(cells(:, 2))~=min(cells(:, 2))
    ctr
    clf
    %select an edge at random
    r = ceil(length(edges)*(rand)); %choose a random edge
    
    edge = edges(find(edges(:, 1)==r),:); %pull up that edge
    edge_col = [edge(2) edge(3); edge(4) edge(5)]; %write the edge in the columnar form
    
    %find the two cells that border the edge
    cell_pair = [];
    for i = 1:n_cells
        cell_col = [cells(i,3) cells(i,4); cells(i,5) cells(i,6); cells(i,7) cells(i,8); cells(i,9) cells(i,10)];
        if (ismember(edge_col, cell_col, 'rows')==[1;1])
            cell_pair = [cell_pair, cells(i, 1)];
        end
    end
    cell_1 = cells(cell_pair(1), :);
    cell_2 = cells(cell_pair(2), :);
    
    %check for the uid
    if cell_1(2) ~= cell_2(2)
        %if not equal, then set uids the same and remove the edge from the
        %display list
        cells(find(cells(:, 2) == cells(cell_pair(1), 2)),2) = min(cell_1(2), cell_2(1));
        cells(find(cells(:, 2) == cells(cell_pair(2), 2)),2) = min(cell_1(2), cell_2(1));
        edges_display(find(edges_display(:, 1)==r),:) = [];
    end
    edges_display;
    cells ;
    ctr = ctr+1;
    
    %pause;
end
toc
show_maze(maze_size, edges_display);
out_sldwrks(edges_display);