Merge pull request #5952 from E7-87-83/newt

Week 160

2 files changed, 146 insertions, 0 deletions

diff --git a/challenge-160/cheok-yin-fung/perl/ch-1.pl b/challenge-160/cheok-yin-fung/perl/ch-1.pl
new file mode 100644
index 0000000000..b4fdf7471d
--- /dev/null
+++ b/challenge-160/cheok-yin-fung/perl/ch-1.pl
@@ -0,0 +1,37 @@
+#!/usr/bin/perl
+# The Weekly Challenge 160
+# Task 1 Four is Magic
+use v5.22.0;
+use warnings;
+
+
+fim($ARGV[0]) if defined($ARGV[0]);
+
+
+
+sub fim {
+    my @num = ("zero", "one", "two", "three", "four", "five",
+               "six", "seven", "eight", "nine");
+    my $spell = "four is magic.";
+    my $c = $_[0];
+    if ($c == 4) {
+        print ucfirst($spell), "\n";
+        return;
+    }
+    $num[$c] = ucfirst($num[$c]);
+    while ($c != 4) {
+        print $num[$c];
+        $c = length $num[$c];
+        print " is $num[$c], ";
+    }
+    print "$spell\n";
+}
+
+
+
+=pod Testing
+
+for (1..9) {
+    fim($_);
+    print "\n";
+}
diff --git a/challenge-160/cheok-yin-fung/perl/ch-2.pl b/challenge-160/cheok-yin-fung/perl/ch-2.pl
new file mode 100644
index 0000000000..8c03ee08a5
--- /dev/null
+++ b/challenge-160/cheok-yin-fung/perl/ch-2.pl
@@ -0,0 +1,109 @@
+#!/usr/bin/perl
+# The Weekly Challenge 160
+# Task 2 Equilibrium Index
+use v5.22.0;
+use warnings;
+use List::Util qw/sum/;
+
+
+say ei(@ARGV) if defined($ARGV[0]);
+
+
+
+sub ei {
+    my @n = @_;
+    my $ind = int $#n/2;
+    my $previous_ind = $ind;
+    my $new_ind = $ind;
+    my $hint_lower = sum(@n[0..$ind-1]);
+    my $hint_upper = sum(@n[$ind+1..$#n]);
+    my $step = 0;
+    my $expired_ind = $ind;
+    my $guessed_step = 0;
+
+    my $success = $hint_lower == $hint_upper;
+    return $ind if $success;
+    
+
+    while (!$success) {
+        return -1 if $ind < 1 or $ind > $#n-1;
+
+        my $cur_val = $n[$ind];
+
+        # Modify the two portions
+        if ($step == +1) {
+            $hint_lower = $hint_lower + $n[$expired_ind];
+            $hint_upper = $hint_upper - $cur_val;
+        }
+        elsif ($step == -1) {
+            $hint_lower = $hint_lower - $cur_val;
+            $hint_upper = $hint_upper + $n[$expired_ind];
+        }
+
+
+        # Decide which direction going to move
+        if ($hint_lower+$cur_val < $hint_upper) {
+            $new_ind = $ind+1;
+        }
+        elsif ($hint_lower > $hint_upper+$cur_val) {
+            $new_ind = $ind-1;
+        }
+        elsif ($hint_lower+$cur_val == $hint_upper) {
+            $new_ind = $ind+$step;
+        }
+        elsif ($hint_lower == $hint_upper+$cur_val) {
+            $new_ind = $ind+$step;
+        }
+
+        else {    
+            if ($hint_lower+$cur_val > $hint_upper) {
+                if ($hint_lower+$cur_val >= $hint_upper-$n[$ind+1]) {
+                    $new_ind = $ind+1;
+                }
+                else {
+                    $new_ind = $ind-1;
+                }
+            }
+            if ($hint_lower < $hint_upper+$cur_val) {
+                $new_ind = $ind-1;
+            }
+
+            if ($hint_lower == $hint_upper+$cur_val 
+                            or 
+                $hint_lower+$cur_val == $hint_upper)
+            {
+                $new_ind = $ind+$step; # follow the previous direction
+            }
+        }    
+
+        # Prepare for the next loop block, or, stop
+        $step = $new_ind-$ind;
+        $success = $hint_lower == $hint_upper;
+        return $ind if $success;
+        return -1 if $guessed_step == -$step; # No back and fro!
+        $guessed_step = $step;
+        ($expired_ind, $ind) = ($ind, $new_ind);
+    }
+}
+
+
+
+use Test::More tests=>50;
+say "TESTING:";
+my @n_temp;
+for my $case (1..50) {
+    $n_temp[$_] = 1 + int rand(40) for (0..31);
+    ok ei_simple(@n_temp) == ei(@n_temp);
+}
+done_testing();
+
+
+
+sub ei_simple {
+    my @seq = @_;
+    for (1..$#seq-1) {
+        return $_ if sum(@seq[0..$_-1]) == sum(@seq[$_+1..$#seq]);
+    }
+    return -1;
+}
+