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NewBoard := function(n)
return List([1..n],
x->List([1..n], y->false));
end;
LegalMove := function(board, n, x, y)
local i;
for i in [1..x-1] do
if board[i][y] or (i < y and board[x-i][y-i]) or
(y <= n-i and board[x-i][y+i]) then
return false;
fi;
od;
return true;
end;
CountSolutionsRec := function(board, n, x)
local result, y;
result := 0;
for y in [1..n] do
if LegalMove(board, n, x, y) then
if x = n then
result := result + 1;
else
board[x][y] := true;
result := result + CountSolutionsRec(board, n, x+1);
board[x][y] := false;
fi;
fi;
od;
return result;
end;
CountSolutions := function(n)
return CountSolutionsRec(NewBoard(n), n, 1);
end;
CountSolutionsPar := function(n)
local i, boards, tasks;
tasks := [];
boards := List([1..n], x->fail);
for i in [1..n] do
boards[i] := NewBoard(n);
boards[i][1][i] := true;
Add(tasks, RunTask(CountSolutionsRec, boards[i], n, 2));
od;
return Sum(List(tasks, TaskResult));
end;
[ Dauer der Verarbeitung: 0.35 Sekunden
(vorverarbeitet)
]
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