Merge pull request #5570 from PerlBoy1967/branch-for-challenge-149

Task 1

1 files changed, 66 insertions, 0 deletions

diff --git a/challenge-149/perlboy1967/perl/ch-1.pl b/challenge-149/perlboy1967/perl/ch-1.pl
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+#!/bin/perl
+
+=pod
+
+The Weekly Challenge - 149
+ - https://perlweeklychallenge.org/blog/perl-weekly-challenge-149/#TASK1
+
+Author: Niels 'PerlBoy' van Dijke
+
+TASK #1 › Fibonacci Digit Sum
+Submitted by: Roger Bell_West
+
+Given an input $N, generate the first $N numbers for which the sum of their 
+digits is a Fibonacci number.
+
+=cut
+
+use v5.16;
+
+use List::Util qw(sum);
+use Memoize;
+use Data::Printer output => 'stdout';
+
+# Prototypes
+sub isFibonacciDigitSum($);
+sub fibonacci ($);
+
+memoize('fibonacci');
+
+my ($N) = @ARGV; $N //= 20;
+
+die "Input must be integer value and >= 1"
+  unless (defined $N and $N =~ m#^[1-9][0-9]*$# and $N >= 1);
+
+my @solutions;
+
+my $n = 0;
+while(scalar(@solutions) < $N) {
+  push(@solutions, $n) if (isFibonacciDigitSum($n));
+  $n++;
+}
+
+p @solutions;
+
+sub isFibonacciDigitSum ($) {
+  my ($n) = @_;
+
+  state @fib;
+  state %fib;
+
+  my $digitSum = sum(split(//, $n));
+  while (scalar(@fib) == 0 or $fib[-1] <= $digitSum) {
+    push(@fib, fibonacci(scalar(@fib)));
+    $fib{$fib[-1]}++;
+  }
+
+  return exists $fib{$digitSum} ? 1 : 0;
+}
+    
+sub fibonacci ($) {
+  my ($n) = @_;
+
+  return 0 if ($n == 0);
+  return 1 if ($n == 1 or $n == 2);
+  return fibonacci($n - 1) + fibonacci($n - 2);
+}