80 lines
1.9 KiB
Text
80 lines
1.9 KiB
Text
MODULE hailst;
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IMPORT Out;
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CONST maxCard = MAX (INTEGER) DIV 3;
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List = 1;
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Count = 2;
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Max = 3;
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VAR a : INTEGER;
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PROCEDURE HailStone (start, type : INTEGER) : INTEGER;
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VAR n, max, count : INTEGER;
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BEGIN
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count := 1;
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n := start;
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max := n;
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LOOP
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IF type = List THEN
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Out.Int (n, 12);
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IF count MOD 6 = 0 THEN Out.Ln END
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END;
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IF n = 1 THEN EXIT END;
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IF ODD (n) THEN
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IF n < maxCard THEN
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n := 3 * n + 1;
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IF n > max THEN max := n END
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ELSE
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Out.String ("Exceeding max value for type INTEGER at: ");
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Out.String (" n = "); Out.Int (start, 12);
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Out.String (" , count = "); Out.Int (count, 12);
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Out.String (" and intermediate value ");
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Out.Int (n, 1);
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Out.String (". Aborting.");
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Out.Ln;
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HALT (2)
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END
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ELSE
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n := n DIV 2
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END;
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INC (count)
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END;
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IF type = Max THEN RETURN max ELSE RETURN count END
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END HailStone;
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PROCEDURE FindMax (num : INTEGER);
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VAR val, maxCount, maxVal, cnt : INTEGER;
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BEGIN
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maxCount := 0;
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maxVal := 0;
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FOR val := 2 TO num DO
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cnt := HailStone (val, Count);
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IF cnt > maxCount THEN
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maxVal := val;
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maxCount := cnt
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END
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END;
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Out.String ("Longest sequence below "); Out.Int (num, 1);
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Out.String (" is "); Out.Int (HailStone (maxVal, Count), 1);
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Out.String (" for n = "); Out.Int (maxVal, 1);
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Out.String (" with an intermediate maximum of ");
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Out.Int (HailStone (maxVal, Max), 1);
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Out.Ln
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END FindMax;
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BEGIN
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a := HailStone (27, List);
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Out.Ln;
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Out.String ("Iterations total = "); Out.Int (HailStone (27, Count), 12);
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Out.String (" max value = "); Out.Int (HailStone (27, Max) , 12);
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Out.Ln;
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FindMax (1000000);
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Out.String ("Done.");
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Out.Ln
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END hailst.
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