AtCoder Regular Contest #004 A

gistfile1.pl

use strict;
use warnings;
use 5.12.4;
 
chomp(my $n = <STDIN>);
chomp(my @line = <STDIN>);
 
my $result = 0;
 
for my $now_point (@line){
    for my $target_point (@line){
        
        my @now_point = split / /, $now_point;
        my @target_point = split / /, $target_point;
        
        my $x = abs ($now_point[0] - $target_point[0]);
        my $y = abs ($now_point[1] - $target_point[1]);
        my $route = sqrt ($x*$x + $y*$y);
        
        if( $result < $route ){
            $result = $route;
        }
    }
}
 
print $result,"\n";