Merge pull request #2431 from oWnOIzRi/week80

add solution for week 80 task 1

1 files changed, 59 insertions, 0 deletions

diff --git a/challenge-080/steven-wilson/perl/ch-1.pl b/challenge-080/steven-wilson/perl/ch-1.pl
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+#!/usr/bin/env perl
+# Solution by Steven Wilson 2nd Oct 2020.
+
+# TASK #1 › Smallest Positive Number
+# Submitted by: Mohammad S Anwar
+#
+# You are given unsorted list of integers @N.
+#
+# Write a script to find out the smallest positive number missing.
+# Example 1:
+#
+# Input: @N = (5, 2, -2, 0)
+# Output: 1
+#
+# Example 2:
+#
+# Input: @N = (1, 8, -1)
+# Output: 2
+#
+# Example 3:
+#
+# Input: @N = (2, 0, -1)
+# Output: 1
+
+use strict;
+use warnings;
+use feature qw/ say /;
+use Test::More;
+use List::MoreUtils qw/ firstidx /;
+
+my @N1_t = ( 5, 2, -2, 0 );
+my @N2_t = ( 1, 8, -1 );
+my @N3_t = ( 2, 0, -1 );
+my @N4_t = ( 5, 2, -2, 0, 1, 3, 4, 6 );
+my @N5_t = ();
+ok( get_smallest_positive_number_missing( \@N1_t ) == 1, "1 missing" );
+ok( get_smallest_positive_number_missing( \@N2_t ) == 2, "1 present" );
+ok( get_smallest_positive_number_missing( \@N3_t ) == 1, "1 missing" );
+ok( get_smallest_positive_number_missing( \@N4_t ) == 7, "larger than max" );
+ok( get_smallest_positive_number_missing( \@N5_t ) == 1, "empty list" );
+done_testing();
+
+sub get_smallest_positive_number_missing {
+    my $unsorted_list_ref = shift;
+    my @sorted_list       = sort { $a <=> $b } @{$unsorted_list_ref};
+    my $index             = firstidx { $_ == 1 } @sorted_list;
+    my $answer            = 1;
+    if ( $index >= 0 ) {
+        my $counter = 1;
+        while ( defined $sorted_list[ $index + ( $counter - 1 ) ]
+            && $sorted_list[ $index + ( $counter - 1 ) ] == ($counter) )
+        {
+            $counter++;
+        }
+        $answer = $counter;
+    }
+    return $answer;
+}
+