Solution to task 2

1 files changed, 66 insertions, 0 deletions

diff --git a/challenge-153/jo-37/perl/ch-2.pl b/challenge-153/jo-37/perl/ch-2.pl
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+++ b/challenge-153/jo-37/perl/ch-2.pl
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+#!/usr/bin/perl -s
+
+use v5.16;
+use Test2::V0;
+use Math::Prime::Util qw(factorial vecsum todigits vecnone);
+use experimental 'signatures';
+
+our ($tests, $examples, $verbose, $base);
+
+$base ||= 10;
+
+run_tests() if $tests || $examples;	# does not return
+
+die <<EOS unless @ARGV;
+usage: $0 [-examples] [-tests] [-verbose] [N]
+
+-examples
+    run the examples from the challenge
+ 
+-tests
+    run some tests
+
+-base=B
+    Check factorions in base B. Default: 10
+
+N
+    Check if N is a factorion in base B
+
+EOS
+
+
+### Input and Output
+
+say 0 + factorion($ARGV[0], $base);
+
+
+### Implementation
+
+sub factorion($n, $base=10) {
+    $n == vecsum map factorial($_), todigits $n, $base;
+}
+
+
+### Examples and tests
+
+sub run_tests {
+    SKIP: {
+        skip "examples" unless $examples;
+
+        ok factorion(145), 'example 1';
+        ok !factorion(125), 'example 2';
+    }
+
+    SKIP: {
+        skip "tests" unless $tests;
+
+        ok factorion(40585), 'one more from WolframAlpha';
+        ok vecnone {factorion($_)} 146 .. 40584;
+        ok factorion(25, 6), '25 = 41(6) = 4! + 1!';
+        ok factorion(26, 6), '26 = 42(6) = 4! + 2!';
+        ok factorion(49, 5), '49 = 144(5) = 1! + 4! + 4!';
+	}
+
+    done_testing;
+    exit;
+}