add solution for week 80 task 2

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+#!/usr/bin/env perl
+# Solution by Steven Wilson 3rd Oct 2020.
+
+# TASK #2 › Count Candies
+# Submitted by: Mohammad S Anwar
+#
+# You are given rankings of @N candidates.
+#
+# Write a script to find out the total candies needed for all
+# candidates. You are asked to follow the rules below:
+# a) You must given at least one candy to each candidate.
+# b) Candidate with higher ranking get more candies than their
+# mmediate neighbors on either side.
+# Example 1:
+#
+# Input: @N = (1, 2, 2)
+#
+# Explanation:
+#
+# Applying rule #a, each candidate will get one candy. So total
+# candies needed so far 3. Now applying rule #b, the first candidate
+# do not get any more candy as its rank is lower than it's
+# neighbours. The second candidate gets one more candy as it's
+# ranking is higher than it's neighbour. Finally the third candidate
+# do not get any extra candy as it's ranking is not higher than
+# neighbour. Therefore total candies required is 4.
+#
+# Output: 4
+#
+# Example 2:
+#
+# Input: @N = (1, 4, 3, 2)
+#
+# Explanation:
+#
+# Applying rule #a, each candidate will get one candy. So total
+# candies needed so far 4. Now applying rule #b, the first candidate
+# do not get any more candy as its rank is lower than it's
+# neighbours. The second candidate gets two more candies as it's
+# ranking is higher than it's both neighbour. The third candidate
+# gets one more candy as it's ranking is higher than it's neighbour.
+# Finally the fourth candidate do not get any extra candy as it's
+# ranking is not higher than neighbour. Therefore total candies
+# required is 7.
+#
+# Output: 7
+#
+
+use strict;
+use warnings;
+use feature qw/ say /;
+use Test::More;
+use List::Util qw/ sum /;
+
+my @N1_t = ( 1, 2, 2 );
+my @N2_t = ( 1, 4, 3, 2 );
+my @N3_t = ( 1, 1, 2, 3 );
+my @N4_t = ( 3, 1, 2, 1 );
+ok( get_total_candies( \@N1_t ) == 4, "example 1" );
+ok( get_total_candies( \@N2_t ) == 7, "example 2" );
+ok( get_total_candies( \@N3_t ) == 7, "last ranking higher" );
+ok( get_total_candies( \@N4_t ) == 6, "first ranking higher" );
+done_testing();
+
+sub get_total_candies {
+    my $rankings_ref    = shift;
+    my @rankings        = @{$rankings_ref};
+    my @candies         = map { 1 } 1 .. scalar @rankings;
+    my $candies_changed = 1;
+    while ($candies_changed) {
+        $candies_changed = 0;
+        for my $i ( 0 .. ( scalar @rankings - 2 ) ) {
+            if ( $rankings[$i] > $rankings[ $i + 1 ]
+                && !( $candies[$i] > $candies[ $i + 1 ] ) )
+            {
+                $candies[$i]++;
+                $candies_changed = 1;
+            }
+            elsif ( $rankings[$i] < $rankings[ $i + 1 ]
+                && !( $candies[$i] < $candies[ $i + 1 ] ) )
+            {
+                $candies[ $i + 1 ]++;
+                $candies_changed = 1;
+            }
+        }
+    }
+    return sum @candies;
+}
+