let
	var matrix : array 9 of array 9 of Integer;
	var set : array 9 of array 9 of array 10 of Boolean;
	var ready : Boolean;
	var i : Integer;
	var j : Integer;
	var k : Integer;
	var l : Integer;
	var x : Integer;
	var y : Integer;
	var z : Integer;
	var tmp : Integer;
	var count : Integer;
	var pos : Integer;
	var pos1 : Integer;
	var pos2 : Integer
in begin
	! Initalisierungen
	
	matrix := [	[0,5,7, 0,0,2, 3,0,6],
			[1,0,2, 7,0,0, 5,0,8],
			[3,8,0, 5,0,9, 7,0,2],
			
			[0,0,5, 1,0,0, 8,0,4],
			[8,1,3, 0,5,0, 2,0,9],
			[7,0,0, 0,0,8, 1,0,5],
			
			[6,3,1, 2,4,5, 9,8,7],
			[5,7,9, 0,0,6, 4,2,1],
			[0,0,8, 9,7,1, 6,5,3]];
	
	i := 0;
	while i < 9 do
	begin
		j := 0;
		while j < 9 do
		begin
			k := 1;
			while k < 10 do
			begin
				if matrix[i][j] = 0 then
					set[i][j][k] := true
!				else if matrix[i][j] = k then
!					set[i][j][k] := true
				else
					set[i][j][k] := false;

					
				k := k + 1;
			end;
			j := j + 1;
		end;
		i := i + 1;
	end;
	
	while \ready do
	begin
!put('a');	

		ready := true;
		
		!! Mögliche Inhalte der Felder feststellen
		
		! Zeilen durchgehen
		i := 0;
		while i < 9 do
		begin
!put('e');	
			! Spalten durchgehen
			j := 0;
			while j < 9 do
			begin
!put('f');	
				if matrix[i][j] = 0 then
				begin
!put('g');	
					! Vorhandene Zahlen in Zeile/Spalte streichen
					k := 0;
					while k < 9 do
					begin
!put('h');	
						tmp := matrix[i][k];
						if  tmp \= 0 then
							set[i][j][tmp] := false
						else ;
						tmp := matrix[k][j];
						if  tmp \= 0 then
							set[i][j][tmp] := false
						else ;
						k := k + 1;
					end;


					
					! Vorhandene Zahlen in Kästchen streichen
					if (0 <= i) /\ (i <= 2) then x := 0
					else if (3 <= i) /\ (i <= 5) then x := 1
					else if (6 <= i) /\ (i <= 8) then x := 2 else;
					if (0 <= j) /\ (j <= 2) then y := 0
					else if (3 <= j) /\ (j <= 5) then y := 1
					else if (6 <= j) /\ (j <= 8) then y := 2 else;
					
					k := 0;
					l := 0;
					while k < 3 do
					begin
!put('i');	
						while l < 3 do
						begin
!put('j');	
							tmp := matrix[k + (x * 3)][l + (y * 3)];
							if tmp \= 0 then
								set[i][j][tmp] := false
							else;
							l := l + 1;
						end;
						k := k + 1;
					end
				end
				else begin ! Bei belegtem Feld set auf false setzen
					k := 1;
					while k < 10 do
					begin
!						if k = matrix[i][j] then
!							set[i][j][k] := true
!						else
							set[i][j][k] := false;
						k := k + 1;
					end
				end;
				j := j + 1;
			end;
			i := i + 1;
		end;
		
		!! Felder berechnen

		! check Feld alleine
		i := 0;
		while i < 9 do
		begin
			j := 0;
			while j < 9 do
			begin
				if matrix[i][j] = 0 then
				begin
					count := 0;
					k := 1;
					while k < 10 do
					begin
						if set[i][j][k] = true then
						begin
							count := count + 1;
							pos := k;
						end else;
						k := k + 1;
					end;
			
					if (count = 1) /\ (matrix[i][j] = 0) then
					begin
!put('c');
!putint(i); put(','); putint(j); put(','); putint(pos);
						matrix[i][j] := pos;
						ready := false;
					end else;
				end else;
				j := j + 1;
			end;
			i := i + 1;
		end;


		
		z := 1;
		while z < 10 do
		begin
		
!put('k');	
			! check row
			i := 0;
			while i < 9 do
			begin
!put('l');	
				count := 0;
				j := 0;
				while j < 9 do
				begin
!put('m');	
					if set[i][j][z] = true then
					begin
						count := count + 1;
						pos := j;
					end else;
					j := j + 1;
				end;
				
				if (count = 1) /\ (matrix[i][pos] = 0) then
				begin
				
!put('n');
!putint(i); put(','); putint(pos); put(','); putint(z);

					matrix[i][pos] := z;
					ready := false;
				end else;
				
				i := i + 1;
			end;

			! check column
			j := 0;
			while j < 9 do
			begin
!put('o');	
				count := 0;
				i := 0;
				while i < 9 do
				begin
					if set[i][j][z] = true then
					begin
						count := count + 1;
						pos := i;
					end else;
					i := i + 1;
				end;
				
				if (count = 1) /\ (matrix[pos][j] = 0) then
				begin
!put('p');	
!putint(pos); put(','); putint(j); put(','); putint(z);
				
					matrix[pos][j] := z;
					ready := false;
				end else;
				
				j := j + 1;
			end;
			
			! check rc
			x := 0;
			while x < 3 do
			begin
!put('q');	
				y := 0;
				while y < 3 do
				begin
!put('r');	
					count := 0;
					i := 0;
					while i < 3 do
					begin
!put('s');	
						j := 0;
						while j < 3 do
						begin
							if set[i + (x * 3)][j + (y * 3)][z] = true then
							begin
								count := count + 1;
								pos1 := i;
								pos2 := j;
							end else;
							j := j + 1;
						end;
						i := i + 1;
					end;
					
					pos1 := pos1 + (x * 3);
					pos2 := pos2 + (y * 3);

					if (count = 1) /\ (matrix[pos1][pos2] = 0) then
					begin
!put('t');
!putint(i+(x*3)); put(','); putint(j+(y*3)); put(','); putint(z);
						matrix[pos1][pos2] := z;
						ready := false;
					end else;
					y := y + 1;

				end;
				x := x + 1;
			end;
			z := z + 1;
		end;


	! Ergebniss ausdrucken
	puteol();
	i := 0;
	while i < 9 do
	begin
		j := 0;
		while j < 9 do
		begin
			putint(matrix[i][j]);
			put(' ');
			j := j + 1;
		end;
		puteol();
		i := i + 1;
	end;
	puteol();


	
	end;
	
	! Mögliche Belegungen der Felder ausgeben
	i := 0;
	while i < 9 do
	begin
		j := 0;
		while j < 9 do
		begin
			puteol(); putint(i); put(','); putint(j); put(':'); put(' ');
			k := 1;
			while k < 10 do
			begin
				if set[i][j][k] = true then
				begin
					putint(k);
					put(' ');
				end else;
				k := k + 1;
			end;
			j := j + 1;
		end;
		i := i + 1;
	end;

end