| Code: | function W = solver(B)
W = zeros(0,4);
%shift everything avoid boundry conditions
thisMat = zeros(size(B)+2);
thisMat(2:end-1,2:end-1)=B;
wiredMat = thisMat;
pegs = unique(nonzeros(thisMat));
IJpairs = arrayfun(@FindPossiblePairs,pegs,'uniformoutput',false);
IJmat = cell2mat(IJpairs);
[bestScores inds] = sort(abs(IJmat(:,1)-IJmat(:,3)) + abs(IJmat(:,2)-IJmat(:,4)) - 2*IJmat(:,5),'ascend');
for MainCounter = 1:length(bestScores)
testedMove = FindShortestPath(IJmat(inds(MainCounter),:));
if ~isempty(testedMove) && size(testedMove,1)<2*IJmat(inds(MainCounter),5)
%thisVal=IJmat(inds(MainCounter),5);
wiredMat(testedMove(:,1),testedMove(:,2))=1;
W=[W;testedMove];
end
end
%shift everything back
W=W-1;
function Moves = FindShortestPath(Pos)
allotedMoves=2*Pos(5);
%since order is unimportant, always create paths with ascending
%numbers for easy of programming
if Pos(1) < Pos(3) || Pos(1) == Pos(3) && Pos(2) < Pos(4)
startPos = Pos(1:2);
endPos = Pos(3:4);
else
startPos = Pos(3:4);
endPos = Pos(1:2);
end
Moves = zeros(allotedMoves,4);
thiscounter = 0;
currentPos = startPos;
while (thiscounter<allotedMoves)
thiscounter=thiscounter+1;
Moves(thiscounter,1:2)=currentPos;
currentDist=sum(abs(currentPos-endPos));
thisMove = repmat(currentPos,[2,1])+eye(2);
thisDist = sum(abs(thisMove - repmat(endPos,[2,1])),2);
if any(thisDist==0)
Moves(thiscounter,3:4)=thisMove(thisDist==0,:);
break
end
if (~wiredMat(thisMove(1,1),thisMove(1,2)) && thisMat(thisMove(1,1),thisMove(1,2)) ~= Pos(5)) && thisDist(1)<currentDist
Moves(thiscounter,3:4)=thisMove(1,:);
elseif (~wiredMat(thisMove(2,1),thisMove(2,2)) && thisMat(thisMove(2,1),thisMove(2,2)) ~= Pos(5)) && thisDist(2)<currentDist
Moves(thiscounter,3:4)=thisMove(2,:);
else
thiscounter=0;
break
end
currentPos = Moves(thiscounter,3:4);
end
%if counter was reset to 0 then Moves will be empty
Moves = Moves(1:thiscounter,:);
return
end
function Pairs = FindPossiblePairs(Value)
[thisI thisJ] = find(thisMat==Value);
if length(thisI)==1
Pairs=[];
return
end
Pairs = zeros(ceil((length(thisI)+1)*(length(thisI)/2)),5);
Pairs(:,5)=Value;
counter=1;
for k=1:length(thisI)
mask = (1:length(thisI))>k;
Pairs(counter:counter+nnz(mask)-1,1:2)=repmat([thisI(k) thisJ(k)],[nnz(mask) 1]);
Pairs(counter:counter+nnz(mask)-1,3:4)=[thisI(mask) thisJ(mask)];
counter=counter+nnz(mask)-1;
end
Pairs=Pairs(1:counter+1,:);
end
end |