58 lines
2.6 KiB
Ada
58 lines
2.6 KiB
Ada
--
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-- Project Euler problem #8
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--
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-- Find the greatest product of five consecutive digits in the 1000-digit
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-- number.
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with Ada.Text_IO;
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use Ada.Text_IO;
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procedure Eight is
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Source : constant String := "73167176531330624919225119674426574742355349194934" &
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"96983520312774506326239578318016984801869478851843" &
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"85861560789112949495459501737958331952853208805511" &
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"12540698747158523863050715693290963295227443043557" &
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"66896648950445244523161731856403098711121722383113" &
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"62229893423380308135336276614282806444486645238749" &
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"30358907296290491560440772390713810515859307960866" &
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"70172427121883998797908792274921901699720888093776" &
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"65727333001053367881220235421809751254540594752243" &
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"52584907711670556013604839586446706324415722155397" &
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"53697817977846174064955149290862569321978468622482" &
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"83972241375657056057490261407972968652414535100474" &
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"82166370484403199890008895243450658541227588666881" &
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"16427171479924442928230863465674813919123162824586" &
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"17866458359124566529476545682848912883142607690042" &
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"24219022671055626321111109370544217506941658960408" &
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"07198403850962455444362981230987879927244284909188" &
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"84580156166097919133875499200524063689912560717606" &
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"05886116467109405077541002256983155200055935729725" &
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"71636269561882670428252483600823257530420752963450";
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function Digits_Product (Input : in String) return Natural is
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Result : Natural := 1;
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begin
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for Item in Input'Range loop
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Result := (Result * Natural'Value (Input (Item .. Item)));
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end loop;
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return Result;
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end Digits_Product;
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Highest : Natural := 0;
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begin
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for Index in 1 .. (Source'Length - 5) loop
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declare
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Sub : constant String := Source (Index .. Index + 4);
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Product : constant Natural := Digits_Product (Sub);
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begin
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if Product > Highest then
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Highest := Product;
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end if;
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end;
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end loop;
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Put_Line ("> Highest product:" & Natural'Image (Highest));
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end Eight;
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