hi, try out this one.

@a = (1,9,3,4,5,6,7,2,4,3);
@b = ("x","y","z","z","a","z","z","z","b","c");
@a=reverse(@a);
@b=reverse(@b);
foreach $l(0 .. scalar @a){
$next=$b[$l+1];
$next1=$b[$l+2];
if($next ne $b[$l]){
push(@c,$a[$l]);
}
}
print reverse @c;
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