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| -rwxr-xr-x | challenge-211/mattneleigh/perl/ch-1.pl | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/challenge-211/mattneleigh/perl/ch-1.pl b/challenge-211/mattneleigh/perl/ch-1.pl new file mode 100755 index 0000000000..27cf557363 --- /dev/null +++ b/challenge-211/mattneleigh/perl/ch-1.pl @@ -0,0 +1,152 @@ +#!/usr/bin/perl + +use strict; +use warnings; +use English; + +################################################################################ +# Begin main execution +################################################################################ + +my @matrices = ( + # Given cases + [ + [4, 3, 2, 1], + [5, 4, 3, 2], + [6, 5, 4, 3] + ], + [ + [1, 2, 3], + [3, 2, 1] + ], + + # Additional test cases + [ + [1, 2, 3, 4, 5, 6 ], + [3, 1, 2, 3, 4, 5 ] + ], + [ + [ 1, 0 ], + [ 2, 1 ], + [ 3, 2 ], + [ 4, 3 ], + [ 5, 4 ], + [ 6, 5 ] + ], + [ + [ 1, 2, 3, 4 ], + [ 4, 1, 2, 3 ], + [ 3, 4, 1, 2 ], + [ 2, 2, 4, 1 ] + ] +); + +print("\n"); +foreach my $matrix (@matrices){ + printf( + "Input: \@matrix = (\n%s )\n", + list_of_lists_to_indented_block( + 22, + @{$matrix} + ) + ); + printf( + "Output: %s\n\n", + is_toeplitz_matrix($matrix) ? "True" : "False" + ); +} + +exit(0); +################################################################################ +# End main execution; subroutines follow +################################################################################ + + + +################################################################################ +# Determine whether a matrix is a Toeplitz matrix- that is to say, a matrix in +# which every diagonal downward and to the right contains the same value in +# every position, e.g.: +# +# $matrix = [ +# [ 1, 2, 3, 4 ], +# [ 4, 1, 2, 3 ], +# [ 3, 4, 1, 2 ], +# [ 2, 3, 4, 1 ] +# ]; +# +# Takes one argument: +# * A ref to a 2-D array that contains a matrix of numbers (see example above) +# Returns: +# * 0 if the matrix is NOT a Toeplitz matrix +# * 1 if the matrix is a Toeplitz matrix +################################################################################ +sub is_toeplitz_matrix{ + use List::Util qw(min); + + my $matrix = shift(); + + # Search above (and including) the main + # diagonal; we skip the last possible + # value of $m because it's a diagonal of + # length one + for my $m (0 .. ($#{$matrix->[0]} - 1)){ + my $value = $matrix->[0][$m]; + + for my $l (1 .. min($#$matrix, $#{$matrix->[0]} - $m)){ + return(0) + unless($matrix->[$l][$m + $l] == $value); + } + } + + # Search below the main diagonal; we + # skip the last possible value of $n + # because it's a diagonal of length one + for my $n (0 .. ($#$matrix - 1)){ + my $value = $matrix->[$n][0]; + + for my $l (1 .. min($#$matrix - $n, $#{$matrix->[0]})){ + return(0) + unless($matrix->[$n + $l][$l] == $value); + } + } + + return(1); + +} + + + +################################################################################ +# Build an indented block of text out of a list of lists +# Each individual list will be presented as the code that would produce an +# array ref of values containing the equivalent data, one per line; a single +# string with embedded newlines is returned +# Takes two arguments: +# * The number of spaces to indent (e.g. 4 ) +# * The list of lists to stringify (e.g. ( [ 1, 2 ], [ 3, 4 ] ) ) +# Returns +# * A single string containing an indented text representation of contents of +# the list of lists (e.g. " [ 1, 2 ]\n [ 3, 4 ]\n" ) +################################################################################ +sub list_of_lists_to_indented_block{ + + my $format_string = (" " x shift()) . "[ %s ]\n"; + + return( + join( + "", + map( + sprintf( + $format_string, + join(", ", @{$_}) + ), + @ARG + ) + ) + ); + +} + + + |