use strict;
use warnings;
use Text::CSV;

my $csv = Text::CSV->new ();
my @expectedFields = qw(X Y Z Time Amplitude);

# Validate the header line
$csv->parse (scalar <DATA>);
my @fieldNames = $csv->fields ();

die "Unexpected field list: @fieldNames\nExpected: @expectedFields\n"
    unless @expectedFields == @fieldNames;

for my $fieldIndex (0 .. $#fieldNames) {
    next if $fieldNames[$fieldIndex] eq $expectedFields[$fieldIndex];

    die "Got field name $fieldNames[$_]. Expected $expectedFields[$fieldIndex]\n";
}

# Find maximums in each 1 second slot
my %maximums; # Keyed by date/time

while (defined (my $line = <DATA>)) {
    $csv->parse ($line);

    my ($x, $y, $z, $time, $amplitude) = $csv->fields ();

    $time =~ s/\.\d{3}//; # Strip fractional seconds
    next if exists $maximums{$time} && $maximums{$time}{amp} >= $amplitude;

    $maximums{$time}{amp} = $amplitude;
    $maximums{$time}{line} = $line;
}

# Output results ordered by time assuming the same date
print $maximums{$_}{line} for sort keys %maximums;

__DATA__
X,Y,Z,Time,Amplitude
2550,531,66,10-12-2007 07:03:08.069,2
2549,529,62,10-12-2007 07:03:08.151,1
2550,531,66,10-12-2007 07:03:09.069,1
2549,529,62,10-12-2007 07:03:09.151,2

##</code><code>##

2550,531,66,10-12-2007 07:03:08.069,2
2549,529,62,10-12-2007 07:03:09.151,2