# You are given an array of integers @A.
#
# Write a script to create an array that represents the smallest element to the
# left of each corresponding index. If none found then use 0.
# Example 1
# Input: @A = (7, 8, 3, 12, 10)
# Output: (0, 7, 0, 3, 3)
#
# For index 0, the smallest number to the left of $A[0] i.e. 7 is none, so we put 0.
# For index 1, the smallest number to the left of $A[1] as compare to 8, in (7) is 7 so we put 7.
# For index 2, the smallest number to the left of $A[2] as compare to 3, in (7, 8) is none, so we put 0.
# For index 3, the smallest number to the left of $A[3] as compare to 12, in (7, 8, 3) is 3, so we put 3.
# For index 4, the smallest number to the left of $A[4] as compare to 10, in (7, 8, 3, 12) is 3, so we put 3 again.
#
# Example 2
# Input: @A = (4, 6, 5)
# Output: (0, 4, 4)
#
# For index 0, the smallest number to the left of $A[0] is none, so we put 0.
# For index 1, the smallest number to the left of $A[1] as compare to 6, in (4) is 4, so we put 4.
# For index 2, the smallest number to the left of $A[2] as compare to 5, in (4, 6) is 4, so we put 4 again.

sub smallest-neighbour(@A) {
    my $smallest = @A[0] + 1;
    gather for @A -> $a {
        if ($smallest <= $a) {
            take $smallest;
        } else {
            $smallest = $a;
            take 0;
        }
    }
}

smallest-neighbour((7, 8, 3, 12, 10)).say;
smallest-neighbour((4, 6, 5)).say;