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| -rwxr-xr-x | challenge-245/jo-37/perl/ch-2.pl | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/challenge-245/jo-37/perl/ch-2.pl b/challenge-245/jo-37/perl/ch-2.pl new file mode 100755 index 0000000000..ef90057f91 --- /dev/null +++ b/challenge-245/jo-37/perl/ch-2.pl @@ -0,0 +1,83 @@ +#!/usr/bin/perl -s + +use v5.24; +use Test2::V0; + +our ($tests, $examples, $verbose); + +run_tests() if $tests || $examples; # does not return + +die <<EOS unless @ARGV; +usage: $0 [-examples] [-tests] [D...] + +-examples + run the examples from the challenge + +-tests + run some tests + +D... + list of decimal digits + +EOS + + +### Input and Output + +say largest_of_three(@ARGV); + + +### Implementation + +sub largest_of_three { + my (@digits, @ind, $mod) = sort @_; + for (0 .. $#digits) { + # The digit modulo 3 + my $digit = $digits[$_] % 3; + # Store indices of digits that are not a multiple of 3 + push $ind[$digit - 1]->@*, $_ if $digit; + # Update the digit sum + $mod += $digit; + } + $mod %= 3; + # Delete the fewest smallest digits to obtain a digit sum divisible + # by 3. + delete @digits[ + !$mod-- ? () : $ind[$mod] ? $ind[$mod][0] : $ind[!$mod]->@[0, 1] + ]; + + # Build the maximum number from the remaining digits in descending + # order or fail. + @digits ? 0 + join '', reverse grep defined, @digits : -1; +} + + +### Examples and tests + +sub run_tests { + SKIP: { + skip "examples" unless $examples; + + is largest_of_three(8, 1, 9), 981, 'example 1';; + is largest_of_three(8, 6, 7, 1, 0), 8760, 'example 2'; + is largest_of_three(1), -1, 'example 3'; + } + + SKIP: { + skip "tests" unless $tests; + + is largest_of_three(6, 4, 3), 63, 'single 1 mod 3'; + is largest_of_three(6, 5, 3), 63, 'single 2 mod 3'; + is largest_of_three(6, 4, 4, 3), 63, 'double 1 mod 3'; + is largest_of_three(6, 5, 5, 3), 63, 'double 2 mod 3'; + is largest_of_three(6, 3), 63, '0 mod 3'; + is largest_of_three(1, 1), -1, 'double 1'; + is largest_of_three(2, 2), -1, 'double 2'; + is largest_of_three(2), -1, 'like example 3'; + is largest_of_three(0, 0, 0, 1), 0, 'zero'; + is largest_of_three(6, 2, 2, 2, 7), 6222, 'remove the largest digit'; + } + + done_testing; + exit; +} |