Add solution 283

Signed-off-by: Thomas Köhler <jean-luc@picard.franken.de>

4 files changed, 124 insertions, 0 deletions

diff --git a/challenge-283/jeanluc2020/blog-1.txt b/challenge-283/jeanluc2020/blog-1.txt
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+http://gott-gehabt.de/800_wer_wir_sind/thomas/Homepage/Computer/perl/theweeklychallenge-283-1.html
diff --git a/challenge-283/jeanluc2020/blog-2.txt b/challenge-283/jeanluc2020/blog-2.txt
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+++ b/challenge-283/jeanluc2020/blog-2.txt
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+http://gott-gehabt.de/800_wer_wir_sind/thomas/Homepage/Computer/perl/theweeklychallenge-283-2.html
diff --git a/challenge-283/jeanluc2020/perl/ch-1.pl b/challenge-283/jeanluc2020/perl/ch-1.pl
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+#!/usr/bin/env perl
+# https://theweeklychallenge.org/blog/perl-weekly-challenge-283/#TASK1
+#
+# Task 1: Unique Number
+# =====================
+#
+# You are given an array of integers, @ints, where every elements appears more
+# than once except one element.
+#
+# Write a script to find the one element that appears exactly one time.
+#
+## Example 1
+##
+## Input: @ints = (3, 3, 1)
+## Output: 1
+#
+## Example 2
+##
+## Input: @ints = (3, 2, 4, 2, 4)
+## Output: 3
+#
+## Example 3
+##
+## Input: @ints = (1)
+## Output: 1
+#
+## Example 4
+##
+## Input: @ints = (4, 3, 1, 1, 1, 4)
+## Output: 3
+#
+############################################################
+##
+## discussion
+##
+############################################################
+#
+# We first count how often each integer appears in the array, then
+# we just return the first one that appears exactly once as a way
+# to short-circuit that part of the execution.
+
+use strict;
+use warnings;
+
+unique_number(3, 3, 1);
+unique_number(3, 2, 4, 2, 4);
+unique_number(1);
+unique_number(4, 3, 1, 1, 1, 4);
+
+sub unique_number {
+   my @ints = @_;
+   print "Input: (", join(", ", @ints), ")\n";
+   my $found;
+   foreach my $n (@ints) {
+      $found->{$n}++;
+   }
+   foreach my $key (keys %$found) {
+      return print "Output: $key\n" if $found->{$key} == 1;
+   }
+   return "Error: No number found exactly once!\n";
+}
diff --git a/challenge-283/jeanluc2020/perl/ch-2.pl b/challenge-283/jeanluc2020/perl/ch-2.pl
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+#!/usr/bin/env perl
+# https://theweeklychallenge.org/blog/perl-weekly-challenge-283/#TASK2
+#
+# Task 2: Digit Count Value
+# =========================
+#
+# You are given an array of positive integers, @ints.
+#
+# Write a script to return true if for every index i in the range 0 <= i < size
+# of array, the digit i occurs exactly the $ints[$i] times in the given array
+# otherwise return false.
+#
+## Example 1
+##
+## Input: @ints = (1, 2, 1, 0)
+## Ouput: true
+##
+## $ints[0] = 1, the digit 0 occurs exactly 1 time.
+## $ints[1] = 2, the digit 1 occurs exactly 2 times.
+## $ints[2] = 1, the digit 2 occurs exactly 1 time.
+## $ints[3] = 0, the digit 3 occurs 0 time.
+#
+## Example 2
+##
+## Input: @ints = (0, 3, 0)
+## Ouput: false
+##
+## $ints[0] = 0, the digit 0 occurs 2 times rather than 0 time.
+## $ints[1] = 3, the digit 1 occurs 0 time rather than 3 times.
+## $ints[2] = 0, the digit 2 occurs exactly 0 time.
+#
+############################################################
+##
+## discussion
+##
+############################################################
+#
+# This requires two passes:
+# 1. count the digits
+# 2. for each index of the array, check whether the digit count value
+#    for this index matches the value in the array.
+
+use strict;
+use warnings;
+
+digit_count_value(1, 2, 1, 0);
+digit_count_value(0, 3, 0);
+
+sub digit_count_value {
+   my @ints = @_;
+   my $digits_counts = {};
+   print "Input: (" . join(", ", @ints) . ")\n";
+   foreach my $digit (@ints) {
+      $digits_counts->{$digit}++;
+   }
+   foreach my $i (0..$#ints) {
+      $digits_counts->{$i} //= 0;
+      return print "Output: false\n" unless $digits_counts->{$i} == $ints[$i];
+   }
+   return print "Output: true\n";
+}