Merge pull request #2098 from oWnOIzRi/c074

add solutions for week 074

2 files changed, 110 insertions, 0 deletions

diff --git a/challenge-074/steven-wilson/perl/ch-1.pl b/challenge-074/steven-wilson/perl/ch-1.pl
new file mode 100644
index 0000000000..3810e1fa17
--- /dev/null
+++ b/challenge-074/steven-wilson/perl/ch-1.pl
@@ -0,0 +1,43 @@
+#!/usr/bin/env perl
+# Week74 Task 1
+# You are given an array of integers of size $N.
+#
+# Write a script to find the majority element. If none found then
+# print -1.
+#
+#     Majority element in the list is the one that appears more than
+#     floor(size_of_list/2).
+#
+# Example 1
+# Input: @A = (1, 2, 2, 3, 2, 4, 2)
+# Output: 2, as 2 appears 4 times in the list which is more than
+# floor(7/2).
+#
+# Example 2
+# Input: @A = (1, 3, 1, 2, 4, 5)
+# Output: -1 as none of the elements appears more than
+# floor(6/2).
+
+use strict;
+use warnings;
+use feature qw/ say /;
+use POSIX qw/ floor /;
+
+my @A1 = ( 1, 2, 2, 3, 2, 4, 2 );
+say find_majority_element( \@A1 );
+my @A2 = ( 1, 3, 1, 2, 4, 5 );
+say find_majority_element( \@A2 );
+
+sub find_majority_element {
+    my $elements_ref = shift;
+    my @elements     = @{$elements_ref};
+    my $majority     = floor( scalar @elements / 2 );
+    my %count_of_elements;
+    map { $count_of_elements{$_}++ } @elements;
+    for ( keys %count_of_elements ) {
+        if ( $count_of_elements{$_} > $majority ) {
+            return $_;
+        }
+    }
+    return -1;
+}
diff --git a/challenge-074/steven-wilson/perl/ch-2.pl b/challenge-074/steven-wilson/perl/ch-2.pl
new file mode 100644
index 0000000000..20b7711f33
--- /dev/null
+++ b/challenge-074/steven-wilson/perl/ch-2.pl
@@ -0,0 +1,67 @@
+#!/usr/bin/env perl
+# Week 74 Task 2
+# FNR Character
+#
+# You are given a string $S.
+#
+# Write a script to print the series of first non-repeating character
+# (left -> right) for the given string. Print # if none found.
+# Example 1
+# Input: $S = ‘ababc’
+# Output: ‘abb#c’
+# Pass 1: “a”, the FNR character is ‘a’
+# Pass 2: “ab”, the FNR character is ‘b’
+# Pass 3: “aba”, the FNR character is ‘b’
+# Pass 4: “abab”, no FNR found, hence ‘#’
+# Pass 5: “ababc” the FNR character is ‘c’
+#
+# Example 2
+# Input: $S = ‘xyzzyx’
+# Output: ‘xyzyx#’
+# Pass 1: “x”, the FNR character is “x”
+# Pass 2: “xy”, the FNR character is “y”
+# Pass 3: “xyz”, the FNR character is “z”
+# Pass 4: “xyzz”, the FNR character is “y”
+# Pass 5: “xyzzy”, the FNR character is “x”
+# Pass 6: “xyzzyx”, no FNR found, hence ‘#’
+
+use strict;
+use warnings;
+use feature qw/ say /;
+use List::MoreUtils qw/ first_index /;
+use Test::More;
+
+my $string1_test = 'ababc';
+my $string2_test = 'xyzzyx';
+ok( first_non_repeating_characters($string1_test) eq 'abb#c',
+    "test \'$string1_test\'" );
+ok( first_non_repeating_characters($string2_test) eq 'xyzyx#',
+    "test \'$string2_test\'" );
+done_testing();
+
+say first_non_repeating_characters($string1_test);
+say first_non_repeating_characters($string2_test);
+
+sub first_non_repeating_characters {
+    my $string = shift;
+    my @non_repeating;
+    my @repeating;
+    my $result;
+    for my $char ( split //, $string ) {
+        my $in_repeating     = grep { $_ eq $char } @repeating;
+        my $in_non_repeating = grep { $_ eq $char } @non_repeating;
+        if ($in_non_repeating) {
+            my $index = first_index { $_ eq $char } @non_repeating;
+            splice @non_repeating, $index, 1;
+            push @repeating, $char;
+        }
+        elsif ( !$in_repeating && !$in_non_repeating ) {
+            push @non_repeating, $char;
+        }
+        scalar @non_repeating > 0
+          ? ( $result .= $non_repeating[-1] )
+          : ( $result .= qw/ # / );
+    }
+    return $result;
+}
+