Data commit

Task/Best-shuffle/PL-I/best-shuffle.pli

@@ -0,0 +1,53 @@
+shuffle: procedure options (main);                  /* 14/1/2011 */
+   declare (s, saves) character (20) varying, c character (1);
+   declare t(length(s)) bit (1);
+   declare (i, k, moves initial (0)) fixed binary;
+
+   get edit (s) (L);
+   put skip list (s);
+   saves = s;
+   t = '0'b;
+   do i = 1 to length (s);
+      if t(i) then iterate; /* This character has already been moved. */
+      c = substr(s, i, 1);
+      k = search (s, c, i+1);
+      if k > 0 then
+         do;
+            substr(s, i, 1) = substr(s, k, 1);
+            substr(s, k, 1) = c;
+            t(k), t(i) = '1'b;
+         end;
+   end;
+
+   do k = length(s) to 2 by -1;
+      if ^t(k) then /* this character wasn't moved. */
+all:     do;
+            c = substr(s, k, 1);
+            do i = k-1 to 1 by -1;
+               if c ^= substr(s, i, 1) then
+                  if substr(saves, i, 1) ^= c then
+                     do;
+                        substr(s, k, 1) = substr(s, i, 1);
+                        substr(s, i, 1) = c;
+                        t(k) = '1'b;
+                        leave all;
+                     end;
+            end;
+         end;
+   end;
+   moves = length(s) - sum(t);
+   put skip edit (s, trim(moves))(a, x(1));
+
+search: procedure (s, c, k) returns (fixed binary);
+   declare s character (*) varying;
+   declare c character (1);
+   declare k fixed binary;
+   declare i fixed binary;
+
+   do i = k to length(s);
+      if ^t(i) then if c ^= substr(s, i, 1) then return (i);
+   end;
+   return (0); /* No eligible character. */
+end search;
+
+end shuffle;