part one:


%macro chess;
data %do i=1 %to 4; chess&i %end;;
        set chess_history;
        %do i=1 %to 4;
         moveall=scan(move,&i,"|","m"); step=&i; output chess&i;
         %end;
run;
data chessall;
        set %do i=1 %to 4; chess&i %end;;
run;

proc sql;
         create table want1 as
         select distinct moveall as unique_chess
         from chessall
        having not missing(moveall);
quit;
%mend;
%chess;

part two:

from above dataset chessall, you can find possible combinations from step 1 to step 4.


hope it helpful and get your reward.

第二个不好做。两个棋子的组合还好，10步以上组合就太多了