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#! /opt/local/bin/perl
#
# zip-zilch-zero.pl
#
# TASK #1 › Zero Matrix
# Submitted by: Mohammad S Anwar
# You are given a matrix of size M x N having only 0s and 1s.
#
# Write a script to set the entire row and column to 0 if an
# element is 0.
#
# Example 1
# Input: [1, 0, 1]
# [1, 1, 1]
# [1, 1, 1]
#
# Output: [0, 0, 0]
# [1, 0, 1]
# [1, 0, 1]
# Example 2
# Input: [1, 0, 1]
# [1, 1, 1]
# [1, 0, 1]
#
# Output: [0, 0, 0]
# [1, 0, 1]
# [0, 0, 0]
#
#
# 2020 colin crain
## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ## ##
use warnings;
use strict;
use feature ":5.26";
## ## ## ## ## MAIN:
## as by challenge definition we only use 1s and 0s,
## concatenate individual rows into strings
## example: 101 111 111 001
my @matrix;
push @matrix, map { [ split //, $_ ] } @ARGV;
my $rows = @matrix;
my $cols = $matrix[0]->@*;
print_matrix(\@matrix, "Input:");
## 0s are considered 'opaque' -- a single 0 occludes the entire row or column
## We pass once through the matrix, row by row, recording the 0 occurence data to
## two arrays, one for rows, the other columns
my @row_zeros = (0) x $rows;
my @col_zeros = (0) x $cols;
for my $row_idx (0..$rows-1) {
my $sum = 0;
for my $col_idx ( 0..$cols-1) {
$sum += $matrix[$row_idx]->[$col_idx];
$col_zeros[$col_idx] |= ! $matrix[$row_idx]->[$col_idx];
}
$row_zeros[$row_idx] = 1 if $sum != $cols;
}
say<<__END__;
Zero Occlusions:
cols: @col_zeros
rows: @row_zeros
__END__
## now we can pass through the matrix again, transferring the occurence
## data back to the rows and columns, zeroing them out as specified
for my $row_idx (0..$rows-1) {
if ($row_zeros[$row_idx] == 1) {
$matrix[$row_idx] = [ (0) x $cols ];
next;
}
for my $col_idx ( 0..$cols-1) {
$matrix[$row_idx]->[$col_idx] = 0 if $col_zeros[$col_idx] == 1;
}
}
print_matrix(\@matrix, "Output:");
## ## ## ## ## SUBS:
sub print_matrix {
my ($matrix, $heading ) = @_;
say "$heading";
for ($matrix->@*) {
say "\t[ ", (join ', ', $_->@*), " ]";
}
}
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