S2OJ/uoj/1/app/libs/uoj-contest-lib.php

<?php
define("CONTEST_NOT_STARTED", 0);
define("CONTEST_IN_PROGRESS", 1);
define("CONTEST_PENDING_FINAL_TEST", 2);
define("CONTEST_TESTING", 10);
define("CONTEST_FINISHED", 20);	

function calcRating($standings, $K = 400) {
	$DELTA = 500;

	$n = count($standings);
	
	$rating = array();
	for ($i = 0; $i < $n; ++$i) {
		$rating[$i] = $standings[$i][2][1];
	}
	
	$rank = array();
	$foot = array();
	for ($i = 0; $i < $n; ) {
		$j = $i;
		while ($j + 1 < $n && $standings[$j + 1][3] == $standings[$j][3]) {
			++$j;
		}
		$our_rk = 0.5 * (($i + 1) + ($j + 1));
		while ($i <= $j) {
			$rank[$i] = $our_rk;
			$foot[$i] = $n - $rank[$i];
			$i++;
		}
	}
	
	$weight = array();
	for ($i = 0; $i < $n; ++$i) {
		$weight[$i] = pow(7, $rating[$i] / $DELTA);
	}
	$exp = array_fill(0, $n, 0);
	for ($i = 0; $i < $n; ++$i)
		for ($j = 0; $j < $n; ++$j)
			if ($j != $i) {
				$exp[$i] += $weight[$i] / ($weight[$i] + $weight[$j]);
			}
	
	$new_rating = array();
	for ($i = 0; $i < $n; $i++) {
		$new_rating[$i] = $rating[$i];
		$new_rating[$i] += ceil($K * ($foot[$i] - $exp[$i]) / ($n - 1));
	}
	
	for ($i = $n - 1; $i >= 0; $i--) {
		if ($i + 1 < $n && $standings[$i][3] != $standings[$i + 1][3]) {
			break;
		}
		if ($new_rating[$i] > $rating[$i]) {
			$new_rating[$i] = $rating[$i];
		}
	}
	
	for ($i = 0; $i < $n; $i++) {
		if ($new_rating[$i] < 0) {
			$new_rating[$i] = 0;
		}
	}
	
	return $new_rating;
}

function calcRatingSelfTest() {
	$tests = [
		[[1500, 1], [1500, 1]],
		[[1500, 1], [1600, 1]],
		[[1500, 1], [1600, 2], [1600, 2]],
		[[1500, 1], [200, 2], [100, 2]],
		[[1500, 1], [100, 2], [200, 2]],
		[[1500, 1], [100, 2], [200, 3]],
		[[1500, 1], [200, 2], [100, 3]],
		[[1500, 1], [3000, 2], [1500, 3]],
		[[1500, 1], [3000, 2], [1500, 3], [1500, 3]],
		[[1500, 1], [1500, 2], [1500, 3], [3000, 4]],
		[[1500, 1], [1500, 2], [10, 3], [1, 4]]
	];
	foreach ($tests as $test_num => $test) {
		print "test #{$test_num}\n";
		
		$standings = array();
		$n = count($test);
		for ($i = 0; $i < $n; $i++) {
			$standings[] = [0, 0, [(string)$i, $test[$i][0]], $test[$i][1]];
		}
		$new_rating = calcRating($standings);
		
		for ($i = 0; $i < $n; $i++) {
			printf("%3d: %4d -> %4d delta: %+4d\n", $test[$i][1], $test[$i][0], $new_rating[$i], $new_rating[$i] - $test[$i][0]);
		}
		print "\n";
	}
}

function genMoreContestInfo(&$contest) {
	$contest['start_time_str'] = $contest['start_time'];
	$contest['start_time'] = new DateTime($contest['start_time']);
	$contest['end_time'] = clone $contest['start_time'];
	$contest['end_time']->add(new DateInterval("PT${contest['last_min']}M"));
	
	if ($contest['status'] == 'unfinished') {
		if (UOJTime::$time_now < $contest['start_time']) {
			$contest['cur_progress'] = CONTEST_NOT_STARTED;
		} else if (UOJTime::$time_now < $contest['end_time']) {
			$contest['cur_progress'] = CONTEST_IN_PROGRESS;
		} else {
			$contest['cur_progress'] = CONTEST_PENDING_FINAL_TEST;
		}
	} else if ($contest['status'] == 'testing') {
		$contest['cur_progress'] = CONTEST_TESTING;
	} else if ($contest['status'] == 'finished') {
		$contest['cur_progress'] = CONTEST_FINISHED;
	}
	$contest['extra_config'] = json_decode($contest['extra_config'], true);
	
	if (!isset($contest['extra_config']['standings_version'])) {
		$contest['extra_config']['standings_version'] = 2;
	}
}

function updateContestPlayerNum($contest) {
	DB::update("update contests set player_num = (select count(*) from contests_registrants where contest_id = {$contest['id']}) where id = {$contest['id']}");
}