make-expert-bracket

#!/usr/bin/perl
#
# Make a bracket code based on a ranking file, e.g., KenPom
# The file should be TSV, with rank in the first column and team name in
# the second.
#
# Usage:
#   ./make-expert-code kenpom.txt

use FindBin 1.51 qw( $RealBin );
use lib $RealBin;

require 'bracket.pl';

my $tourney = "2024m";
setup("$tourney/teams");
while (my ($seed, $name) = each %team) {
	if ($name =~ m#^(.*)/(.*)$#) {
		$seed_by_name{$1} = $seed;
		$seed_by_name{$2} = $seed;
	}
	else {
		$seed_by_name{$name} = $seed;
	}
}

# read team alias file
open(INP, "<teams-espn-map");
while (<INP>) {
  /(.*) => (.*)/ || next;
  $rename{$1} = $2;
}

# read the rank file into %rank
while (<>) {
  chomp;
	my ($r, $t) = split/\t/;
	$t = $rename{$t} || $t;
	$rank{$t} = $r;
}

# use %rank to predict @winner and @upset values
#   $winner[game] = seed
#   $upset[game] is true if the lower seed (higher number) wins
for (my $g=63; $g>=1; $g--) {
  $game{$g} ||= $winner[$g*2+1] . "," . $winner[$g*2];
	my ($s1, $s2) = split/,/, $game{$g};
	if ($team{$s2} =~ /\//) {
		my ($pi1, $pi2) = split/\//, $team{$s2};
		print "game ${g}PI: $s2: ";
		$team{$s2} = guess_winner($pi1, $pi2);
		print " -> $team{$s2} ($s2)\n";
	}
	print "game $g: $game{$g}: ";
	my $wteam = guess_winner($team{$s1}, $team{$s2});
	my $wseed = $seed_by_name{$wteam};
	print " -> $wteam ($wseed)\n";
	$winner[$g] = $wseed;
	$upset[$g] = $wseed == min($s1, $s2) ? 0 : 1;
}

# print out the code corresponding to @upset
foreach $i (0..7) { $code[$i] = 0; }
foreach $i (1..63) {
	if ($upset[$i]) {
		$code[int((63-$i)/8)] |= (1<<((63-$i)%8));
	}
}
print join(".",@code), "\n";

# given two team names, predict the winner and return its name
sub guess_winner {
	my ($t1, $t2) = @_;
	my $r1 = $rank{$t1};
	my $r2 = $rank{$t2};
	if (!$r1) { print "$t1 has no rank\n"; exit 1; }
	if (!$r2) { print "$t2 has no rank\n"; exit 1; }
	print "$t1 ($r1) vs $t2 ($r2)";
	if ($r1 < $r2) { return $t1; } else { return $t2; }
}

sub min {
	$_[0] < $_[1] ? $_[0] : $_[1]
}