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Diffstat (limited to 'challenge-078/colin-crain/raku/ch-1.raku')
| -rw-r--r-- | challenge-078/colin-crain/raku/ch-1.raku | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/challenge-078/colin-crain/raku/ch-1.raku b/challenge-078/colin-crain/raku/ch-1.raku new file mode 100644 index 0000000000..e528ed3e06 --- /dev/null +++ b/challenge-078/colin-crain/raku/ch-1.raku @@ -0,0 +1,51 @@ +#!/usr/bin/env perl6 +# +# +# follow-the-leader.raku +# +# TASK #1 › Leader Element +# Submitted by: Mohammad S Anwar +# You are given an array @A containing distinct integers. +# +# Write a script to find all leader elements in the array @A. Print (0) +# if none found. +# +# An element is leader if it is greater than all the elements to its +# right side. +# +# Example 1: +# Input: @A = (9, 10, 7, 5, 6, 1) +# Output: (10, 7, 6, 1) +# Example 2: +# Input: @A = (3, 4, 5) +# Output: (5) +# +# method: working from the end, the tail element is by definition the +# "leader" of none. From there a running local maximum is +# established among elements already seen and the focus moves one +# element to the left. If the element is greater than the local +# maximum, it is the leader and becomes the new maximum. Leaders are +# propgated to the output array, which needs to be revered back to +# +# +# 2020 colin crain +## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## + + + +unit sub MAIN (*@input) ; + +## in +@input.elems == 0 and @input = 9, 10, 7, 5, 6, 1; + +## work +my $max = -Inf; +my @output = @input.reverse + .map( { $_ > $max ?? ($max = $_) !! Nil } ) + .grep( *.defined ); +@output .= reverse; + +## out +say " input: ", @input; +say "output: ", @output; + |