June 2018 Update

Task/Sudoku/Ada/sudoku.ada

@@ -0,0 +1,108 @@
+with Ada.Text_IO;
+
+procedure Sudoku is
+   type sudoku_ar_t is array ( integer range 0..80 ) of integer range 0..9;
+   FINISH_EXCEPTION : exception;
+
+   procedure prettyprint(sudoku_ar: sudoku_ar_t);
+   function checkValidity( val : integer; x : integer; y : integer;  sudoku_ar: in  sudoku_ar_t) return Boolean;
+   procedure placeNumber(pos: Integer; sudoku_ar: in out sudoku_ar_t);
+   procedure solve(sudoku_ar: in out sudoku_ar_t);
+
+
+   function checkValidity( val : integer; x : integer; y : integer;  sudoku_ar: in  sudoku_ar_t) return Boolean
+   is
+   begin
+      for i in 0..8 loop
+
+         if ( sudoku_ar( y * 9 + i ) = val or sudoku_ar( i * 9 + x ) = val ) then
+            return False;
+         end if;
+      end loop;
+
+      declare
+         startX : constant integer := ( x / 3 ) * 3;
+         startY : constant integer := ( y / 3 ) * 3;
+      begin
+         for i in startY..startY+2 loop
+            for j in startX..startX+2 loop
+               if ( sudoku_ar( i * 9 +j ) = val ) then
+                  return False;
+               end if;
+            end loop;
+         end loop;
+         return True;
+      end;
+   end checkValidity;
+
+
+
+   procedure placeNumber(pos: Integer; sudoku_ar: in out sudoku_ar_t)
+   is
+   begin
+      if ( pos = 81 ) then
+         raise FINISH_EXCEPTION;
+      end if;
+      if (  sudoku_ar(pos) > 0 ) then
+         placeNumber(pos+1, sudoku_ar);
+         return;
+      end if;
+      for n in 1..9 loop
+         if( checkValidity( n,  pos mod 9, pos / 9 , sudoku_ar ) ) then
+            sudoku_ar(pos) := n;
+            placeNumber(pos + 1, sudoku_ar );
+            sudoku_ar(pos) := 0;
+         end if;
+      end loop;
+   end placeNumber;
+
+
+   procedure solve(sudoku_ar: in out sudoku_ar_t)
+   is
+   begin
+      placeNumber( 0, sudoku_ar );
+      Ada.Text_IO.Put_Line("Unresolvable !");
+   exception
+      when FINISH_EXCEPTION =>
+         Ada.Text_IO.Put_Line("Finished !");
+         prettyprint(sudoku_ar);
+   end solve;
+
+
+
+
+   procedure prettyprint(sudoku_ar: sudoku_ar_t)
+   is
+      line_sep   : constant String  := "------+------+------";
+   begin
+      for i in sudoku_ar'Range loop
+         Ada.Text_IO.Put(sudoku_ar(i)'Image);
+         if (i+1) mod 3 = 0 and not((i+1) mod 9 = 0) then
+            Ada.Text_IO.Put("|");
+         end if;
+         if (i+1) mod 9 = 0 then
+            Ada.Text_IO.Put_Line("");
+         end if;
+         if (i+1) mod 27 = 0 then
+            Ada.Text_IO.Put_Line(line_sep);
+         end if;
+      end loop;
+   end prettyprint;
+
+
+   sudoku_ar : sudoku_ar_t :=
+     (
+      8,5,0,0,0,2,4,0,0,
+      7,2,0,0,0,0,0,0,9,
+      0,0,4,0,0,0,0,0,0,
+      0,0,0,1,0,7,0,0,2,
+      3,0,5,0,0,0,9,0,0,
+      0,4,0,0,0,0,0,0,0,
+      0,0,0,0,8,0,0,7,0,
+      0,1,7,0,0,0,0,0,0,
+      0,0,0,0,3,6,0,4,0
+     );
+
+begin
+   solve( sudoku_ar );
+end Sudoku;