data test;
input x @@;
cards;
1 1 2 3 1 2 1 2 1 2 1 1 2 3 4 5 6
;
run;
data want;
set test;
id=_n_;
run;
proc sort data=want;
by descending id;
run;
data want;
set want;
retain y;
dif=dif(x);
if _n_=1 then y=x;
else if dif>=0 then y=x;
drop dif;
run;
proc sort data=want;
by id;
run;
proc print;run;