Data update

Task/Mian-Chowla-sequence/ALGOL-68/mian-chowla-sequence.alg

@@ -8,7 +8,8 @@ BEGIN
     [ max mc ]INT mc;
     INT curr size       :=      0; # initial size of the array     #
     INT size increment   = 10 000; # size to increase the array by #
-    REF[]BOOL is sum    := HEAP[ 1 : 0 ]BOOL;
+    HEAP[ 1 : 0 ]BOOL empty sum;
+    REF[]BOOL is sum    := empty sum;
     INT mc count        := 1;
     FOR i WHILE mc count <= max mc DO
         # assume i will be part of the sequence                    #

Task/Mian-Chowla-sequence/ALGOL-W/mian-chowla-sequence.alg

@@ -0,0 +1,55 @@
+% Find Mian-Chowla numbers: an
+                     where: ai = 1,
+                       and: an = smallest integer such that ai + aj is unique
+                                             for all i, j in 1 .. n && i <= j
+%
+begin
+    record HashedSum ( integer hSum; reference(HashedSum) hNext );
+    integer  HASH_MOD, MAX_MC;
+    HASH_MOD := 10000;
+    MAX_MC   :=   100;
+    begin
+        % hash table of sums of the sequence elements encountered so far %
+        reference(HashedSum) array sums ( 0 :: HASH_MOD - 1 );
+        % table of the sequence elements encountered so far              %
+        integer              array mc   ( 1 :: MAX_MC       );
+        integer                    mcCount, i;
+        for i := 0 until HASH_MOD - 1 do sums( i ) := null;
+        mcCount := 1;
+        i       := 0;
+        while begin i := i + 1; mcCount <= MAX_MC end do begin
+            logical isUnique;
+            integer mcPos;
+            % assume i will be part of the sequence                      %
+            mc( mcCount ) := i;
+            % check the sums                                             %
+            isUnique      := true;
+            mcPos         := 0;
+            while begin mcPos := mcPos + 1; mcPos <= mcCount and isUnique end do begin
+                integer s;
+                reference(HashedSum) hs;
+                % attempt to find the sum in the hash table              %
+                s  := i + mc( mcPos );
+                hs := sums( s rem HASH_MOD );
+                while hs not = null and s not = hSum(hs) do hs := hNext(hs);
+                isUnique := hs = null
+            end while_isUnique;
+            if isUnique then begin
+                % i is a sequence element - store its sums               %
+                for mcPos   := 1 until mcCount do begin
+                    integer newSum, sumHash;
+                    newSum  := i + mc( mcPos );
+                    sumHash := newSum rem HASH_MOD;
+                    sums( sumHash ) := HashedSum( newSum, sums( sumHash ) )
+                end for_mcPos ;
+                mcCount := mcCount + 1
+            end if_isUnique
+        end while_mcCount_le_MAX_MC;
+
+        % print parts of the sequence                                  %
+        write( "Mian Chowla sequence elements 1..30:" );write();
+        for i :=  1 until  30 do writeon( i_w := 1, s_w := 0, " ", mc( i ) );
+        write( "Mian Chowla sequence elements 91..100:" );write();
+        for i := 91 until 100 do writeon( i_w := 1, s_w := 0, " ", mc( i ) )
+    end
+end.

Task/Mian-Chowla-sequence/EasyLang/mian-chowla-sequence.easy

@@ -0,0 +1,37 @@
+func[] mian_chowla n .
+   len mc[] n
+   mc[1] = 1
+   is[] = [ 0 1 ]
+   for i = 2 to n
+      j = mc[i - 1]
+      repeat
+         j += 1
+         mc[i] = j
+         for k = 1 to i
+            sum = mc[k] + j
+            if sum > len is[]
+               len is[] sum + 10000
+            .
+            if is[sum] = 1
+               isnew[] = [ ]
+               break 1
+            .
+            isnew[] &= sum
+         .
+         until len isnew[] > 0
+      .
+      for v in isnew[]
+         is[v] = 1
+      .
+   .
+   return mc[]
+.
+mc[] = mian_chowla 100
+for i to 30
+   write mc[i] & " "
+.
+print ""
+print ""
+for i = 91 to 100
+   write mc[i] & " "
+.