MODULE Queens; IMPORT Out; VAR solutionsCount, ln: INTEGER; x: ARRAY 8 OF INTEGER; a: ARRAY 8 OF BOOLEAN; b, c: ARRAY 15 OF BOOLEAN; PROCEDURE Write; VAR i: INTEGER; BEGIN FOR i := 0 TO LEN(x) - 1 DO Out.Int(x[i], 2) END; INC(ln); IF ln = 4 THEN Out.Ln; ln := 0 ELSE Out.String(" ") END END Write; PROCEDURE Init; VAR i: INTEGER; BEGIN FOR i := 0 TO LEN(a) - 1 DO a[i] := TRUE; x[i] := -1 END; FOR i := 0 TO LEN(b) - 1 DO b[i] := TRUE; c[i] := TRUE END; solutionsCount := 0; ln := 0 END Init; PROCEDURE Try(i: INTEGER); VAR j: INTEGER; BEGIN IF i < LEN(x) THEN FOR j := 0 TO LEN(x) - 1 DO IF a[j] & b[i + j] & c[i - j + 7] THEN x[i] := j; a[j] := FALSE; b[i + j] := FALSE; c[i - j + 7] := FALSE; Try(i + 1); x[i] := -1; a[j] := TRUE; b[i + j] := TRUE; c[i - j + 7] := TRUE END END ELSE Write; INC(solutionsCount) END END Try; PROCEDURE All*; BEGIN Init; Try(0); Out.String("Count of solutions: "); Out.Int(solutionsCount, 0); Out.Ln END All; END Queens.