Merge pull request #9771 from pme/challenge-236

challenge-236

2 files changed, 173 insertions, 0 deletions

diff --git a/challenge-236/peter-meszaros/perl/ch-1.pl b/challenge-236/peter-meszaros/perl/ch-1.pl
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+++ b/challenge-236/peter-meszaros/perl/ch-1.pl
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+#!/usr/bin/env perl
+#
+# You are asked to sell juice each costs $5. You are given an array of bills.
+# You can only sell ONE juice to each customer but make sure you return exact
+# change back. You only have $5, $10 and $20 notes. You do not have any change in
+# hand at first.
+# 
+# Write a script to find out if it is possible to sell to each customers with
+# correct change.
+# Example 1
+# 
+# Input: @bills = (5, 5, 5, 10, 20)
+# Output: true
+# 
+# From the first 3 customers, we collect three $5 bills in order.
+# From the fourth customer, we collect a $10 bill and give back a $5.
+# From the fifth customer, we give a $10 bill and a $5 bill.
+# Since all customers got correct change, we output true.
+# 
+# Example 2
+# 
+# Input: @bills = (5, 5, 10, 10, 20)
+# Output: false
+# 
+# From the first two customers in order, we collect two $5 bills.
+# For the next two customers in order, we collect a $10 bill and give back a $5 bill.
+# For the last customer, we can not give the change of $15 back because we only
+# have two $10 bills.
+# Since not every customer received the correct change, the answer is false.
+# 
+# Example 3
+# 
+# Input: @bills = (5, 5, 5, 20)
+# Output: true
+# 
+
+use strict;
+use warnings;
+use Test2::V0 -no_srand => 1;
+use Data::Dumper;
+
+my $cases = [
+	[5, 5, 5, 10, 20],
+	[5, 5, 10, 10, 20],
+	[5, 5, 5, 20],
+];
+
+sub exact_change
+{
+	my $bill = shift;
+
+    my %change = (
+         5 => 0,
+        10 => 0,
+        20 => 0,
+    );
+    my $ret = 1;
+	for my $bill (@$bill) {
+        ++$change{$bill};
+		if ($bill == 10) {
+            if ($change{5}) {
+                --$change{5};
+            } else {
+                $ret = 0;
+                last;
+            }
+		} elsif ($bill == 20) {
+            if ($change{5} && $change{10}) {
+                --$change{5};
+                --$change{10};
+            } elsif ($change{5} >= 3) {
+                $change{5} -= 3;
+            } else {
+                $ret = 0;
+                last;
+            }
+		}
+	}
+
+	return $ret;
+}
+
+is(exact_change($cases->[0]), 1, 'Example 1');
+is(exact_change($cases->[1]), 0, 'Example 2');
+is(exact_change($cases->[2]), 1, 'Example 3');
+done_testing();
+
+exit 0;
diff --git a/challenge-236/peter-meszaros/perl/ch-2.pl b/challenge-236/peter-meszaros/perl/ch-2.pl
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+++ b/challenge-236/peter-meszaros/perl/ch-2.pl
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+#!/usr/bin/env perl
+#
+# You are given an array of unique integers.
+# 
+# Write a script to determine how many loops are in the given array.
+# 
+#     To determine a loop: Start at an index and take the number at #
+#     array[index] and then proceed to that index and continue this until you end up
+#     at the starting index.
+# 
+# 
+# Example 1
+# 
+# Input: @ints = (4,6,3,8,15,0,13,18,7,16,14,19,17,5,11,1,12,2,9,10)
+# Output: 3
+# 
+# To determine the 1st loop, start at index 0, the number at that index is 4,
+# proceed to index 4, the number at that index is 15, proceed to index 15 and so
+# on until you're back at index 0.
+# 
+# Loops are as below:
+# [4 15 1 6 13 5 0]
+# [3 8 7 18 9 16 12 17 2]
+# [14 11 19 10]
+# 
+# Example 2
+# 
+# Input: @ints = (0,1,13,7,6,8,10,11,2,14,16,4,12,9,17,5,3,18,15,19)
+# Output: 6
+# 
+# Loops are as below:
+# [0]
+# [1]
+# [13 9 14 17 18 15 5 8 2]
+# [7 11 4 6 10 16 3]
+# [12]
+# [19]
+# 
+# Example 3
+# 
+# Input: @ints = (9,8,3,11,5,7,13,19,12,4,14,10,18,2,16,1,0,15,6,17)
+# Output: 1
+# 
+# Loop is as below:
+# [9 4 5 7 19 17 15 1 8 12 18 6 13 2 3 11 10 14 16 0]
+# 
+
+use strict;
+use warnings;
+use Test2::V0 -no_srand => 1;
+use Data::Dumper;
+
+my $cases = [
+    #0  1   2   3   4  5   6   7   8   9  10  11  12 13  14 15  16  17  18  19
+	[4, 6,  3,  8, 15, 0, 13, 18,  7, 16, 14, 19, 17, 5, 11, 1, 12,  2,  9, 10],
+	[0, 1, 13,  7,  6, 8, 10, 11,  2, 14, 16,  4, 12, 9, 17, 5,  3, 18, 15, 19],
+	[9, 8,  3, 11,  5, 7, 13, 19, 12,  4, 14, 10, 18, 2, 16, 1,  0, 15,  6, 17],
+];
+
+sub array_loops
+{
+	my $l = shift;
+
+	my $nloop = 0;
+    my %visited;
+	for my $start (0..$#$l) {
+        next if defined $visited{$start};
+        my $next = $l->[$start];
+		while ($next != $start || not defined $visited{$next}) {
+            ++$visited{$next};
+            $next = $l->[$next];
+        }
+        ++$nloop if $next == $start;
+	}
+
+	return $nloop;
+}
+
+is(array_loops($cases->[0]),   3, 'Example 1');
+is(array_loops($cases->[1]),   6, 'Example 2');
+is(array_loops($cases->[2]),   1, 'Example 3');
+done_testing();
+
+exit 0;
+