#!/usr/bin/perl

use strict;
use warnings;


$| = 1;   # set print buffering to not buffe



print "OLD MATRIX:\n";
my $matrix = [ [ 4, 3, 2, 1],
               [ 1, 2, 1, 1],
               [ 4, 1, 3, 4],
               [ 5, 6, 5, 4] ];
   printMatrix($matrix);
my $nRows = scalar(@{$matrix});
my $nCols = scalar(@{$matrix->[0]});

my $newMatrix = [];
print "\n";
foreach my $row (0..($nRows-1)){
  my $doIt = 1;
  foreach my $col (1..($nCols-1)){
     if(abs($matrix->[$row][($col-1)] - $matrix->[$row][$col])>1){
       $doIt = 0;
       print "*** DROPPING ROW $row ***\n";
       last;
     }
  }
  push(@{$newMatrix},$matrix->[$row]) if($doIt);
}
print "\n";
print "NEW MATRIX:\n";
printMatrix($newMatrix);


exit(0);

sub printMatrix {
  my($matrix) = @_;
  my $nRows = scalar(@{$matrix});
  return 0 if($nRows==0);
  my $nCols = scalar(@{$matrix->[0]});
  return 0 if($nCols==0);
  foreach my $row (0..($nRows-1)){
    print "   ROW $row: ";
    foreach my $col (0..($nCols-1)){
      printf "%3d  ",$matrix->[$row][$col];
    }
    print "\n";
  }
  return 1;
}


##</code><code>##

OLD MATRIX:
   ROW 0:   4    3    2    1  
   ROW 1:   1    2    1    1  
   ROW 2:   4    1    3    4  
   ROW 3:   5    6    5    4  

*** DROPPING ROW 2 ***

NEW MATRIX:
   ROW 0:   4    3    2    1  
   ROW 1:   1    2    1    1  
   ROW 2:   5    6    5    4