Merge pull request #2124 from E7-87-83/master

Cheok Yin's submission for challenge #074

2 files changed, 97 insertions, 0 deletions

diff --git a/challenge-074/cheok-yin-fung/perl/ch-1.pl b/challenge-074/cheok-yin-fung/perl/ch-1.pl
new file mode 100644
index 0000000000..0b67899143
--- /dev/null
+++ b/challenge-074/cheok-yin-fung/perl/ch-1.pl
@@ -0,0 +1,49 @@
+#!/usr/bin/perl
+# ref:
+# https://en.wikipedia.org/wiki/Boyer%E2%80%93Moore_majority_vote_algorithm
+# Perl Weekly Challenge #074 Task 1 Majority Element
+# task statement: 
+# Write a script to find the majority element. 
+# If none found then print -1.
+# Usage: ch-1.pl [ARRAY]
+use strict;
+use warnings;
+#use Test::More tests => 3;
+
+
+sub verify {
+    my @array = @{$_[0]};
+    my $m = $_[1];
+    my $c = 0;
+    for (@array) {
+        $c++ if $m==$_;
+    }
+    return ($c > (scalar @array)/2.0 ? 1 : undef);
+}
+
+sub bm_majority_vote_alg {
+    my @array = @{$_[0]};
+    my $i = 0;
+    my $m;
+    for (@array) {
+        if ($i == 0) {
+            $m = $_;
+            $i++
+        }
+        else {
+            $m == $_ ? $i++ : $i--;
+        }
+    }
+    
+
+    return ( verify(\@array, $m) ? $m : -1 );
+}
+
+
+print bm_majority_vote_alg(\@ARGV);
+
+=pod
+is_deeply(  bm_majority_vote_alg( [1, 2, 2, 3, 2, 4, 2] ) , "2", "example1 provided");
+is_deeply(  bm_majority_vote_alg( [1, 3, 1, 2, 4, 5] ) , "-1", "example2 provided");
+is_deeply(  bm_majority_vote_alg( [2, 2, 2, 3, 1, 3, 4] ) , "-1", "array: 2223134");
+=cut
diff --git a/challenge-074/cheok-yin-fung/perl/ch-2.pl b/challenge-074/cheok-yin-fung/perl/ch-2.pl
new file mode 100644
index 0000000000..bae04b73b3
--- /dev/null
+++ b/challenge-074/cheok-yin-fung/perl/ch-2.pl
@@ -0,0 +1,48 @@
+#!/usr/bin/perl
+# Perl Weekly Challenge #074 Task 2 FNR character
+# task statement:
+# 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.
+# Usage: ch-2.pl [string]
+
+use strict;
+use warnings;
+#use Test::More tests => 5;
+
+sub fnr {
+    my @uniquestack;
+    my %charcount;
+    my $ans = "";
+    my @characters = split //, $_[0];
+    for my $char (@characters) {
+        if (!exists $charcount{$char} ) {
+            push @uniquestack , $char;
+            $charcount{$char} = 1;
+            $ans .= $char;
+        } 
+        else {
+            $charcount{$char}++;
+            @uniquestack = grep { $charcount{$_} == 1 } @uniquestack;
+            $ans .= (scalar @uniquestack != 0) ? $uniquestack[-1]  : "#";
+        }
+    }
+    return $ans;
+
+}
+
+print fnr("$ARGV[0]");
+
+=pod
+is_deeply( fnr("ababc") , "abb#c", "example1 provided");
+is_deeply( fnr("xyzzyx") , "xyzyx#", "example2 provided");
+is_deeply( fnr("abcdef") , "abcdef", "trival");
+is_deeply( fnr("aaabbb") , "a##b##", "repeats");
+is_deeply( fnr(
+  "thequickbrownfoxjumpsoverthelazydog") , 
+  "thequickbrownffxjjmpssvvvvvvlazyddg",
+  "long sentence"
+);
+=cut