79 lines
1.3 KiB
Plaintext
79 lines
1.3 KiB
Plaintext
(*
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adapted to Oberon-07 by 0CodErr, KolibriOS team
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*)
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(* Find sequence of digits 0, 1, 2 and of lengths 1 ... 90, such
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that they contain no two adjacent subsequences that are equal *)
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MODULE sequence012;
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IMPORT In, Out, Console;
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CONST
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maxlength = 75;
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VAR
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n: INTEGER;
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good: BOOLEAN;
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s: ARRAY maxlength OF INTEGER;
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PROCEDURE printsequence;
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VAR
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k: INTEGER;
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BEGIN
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Out.Char(" ");
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FOR k := 1 TO n DO Out.Int(s[k], 1) END;
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Out.Ln
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END printsequence;
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PROCEDURE changesequence;
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BEGIN
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IF s[n] = 3 THEN
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DEC(n);
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changesequence
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ELSE
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s[n] := s[n] + 1
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END
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END changesequence;
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PROCEDURE try;
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VAR
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i, l, nhalf: INTEGER;
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BEGIN
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IF n <= 1 THEN
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good := TRUE
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ELSE
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l := 0; nhalf := n DIV 2;
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REPEAT
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INC(l); i := 0;
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REPEAT
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good := s[n - i] # s[n - l - i];
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INC(i)
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UNTIL good OR (i = l)
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UNTIL ~good OR (l >= nhalf)
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END
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END try;
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BEGIN
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Console.open;
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n := 0;
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REPEAT
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INC(n);
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s[n] := 1; try;
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WHILE ~good DO
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changesequence;
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try
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END;
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printsequence
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UNTIL n >= maxlength - 1;
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In.Ln;
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Console.exit(TRUE)
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END sequence012. |