use Benchmark 'cmpthese';
use List::BinarySearch::XS 'binsearch_pos';
use List::Util 'first';

my @lookup_values = (
    [ 25000,        2500        ],
    [ 50000,        5000        ],
    [ 150000,       12500       ],
    [ 225000,       25000       ],
    [ 300000,       37500       ],
    [ 600000,       60000       ],
    [ 1200000,      120000      ],
    [ 3600000,      300000      ],
    [ 5400000,      600000      ],
    [ 10800000,     900000      ],
    [ 21600000,     1800000     ],
    [ 43200000,     3600000     ],
    [ 64800000,     7200000     ],
    [ 129600000,    10800000    ],
    [ 216000000,    21600000    ],
    [ 432000000,    43200000    ],
    [ 864000000,    86400000    ],
    [ 1728000000,   172800000   ],
    [ 3024000000,   345600000   ],
    [ 6048000000,   604800000   ],
    [ 12096000000,  1209600000  ],
    [ 31557600000,  2629800000  ],
    [ 63115200000,  5259600000  ],
    [ 78894000000,  7889400000  ],
    [ 157788000000, 15778800000 ],
);  

my @tests = ( 0, 100, 25000, 50000, ( map { int rand 160000000000 } 1 .. 10000 ), 160000000000 );

sub simple_lookup {
    my( $n, $h ) = @_;
    $n < $_->[0] && return $_->[1] for @$h;
    return 31557600000;
}   

sub bsearch_lookup {
    my( $n, $h ) = @_;
    my $pos = binsearch_pos { $a <=> $b->[0] } $n+1, @$h;
    $pos > $#$h && return 31557600000;
    return $h->[$pos][1]; 
}   

sub first_lookup {
    my( $n, $h ) = @_;
    my $res = first {  $n < $_->[0] } @$h;
    return ref $res ? $res->[1] : 31557600000;
}   

cmpthese( -5, {
    simple  => sub { my @result = map{ bsearch_lookup( $_, \@lookup_values ) } @tests; },
    bsearch => sub { my @result = map{ simple_lookup ( $_, \@lookup_values ) } @tests; },
    first   => sub { my @result = map{ first_lookup  ( $_, \@lookup_values ) } @tests; },
});