php实现单淘汰赛制

PHP实现单淘汰赛制的方法

单淘汰赛制是一种竞赛形式，每场比赛的败者被淘汰，胜者进入下一轮，直到决出冠军。以下是实现单淘汰赛制的几种方法：

生成比赛对阵表

使用数组存储参赛选手或队伍，通过循环生成对阵表：

$players = ['选手1', '选手2', '选手3', '选手4', '选手5', '选手6', '选手7', '选手8'];
shuffle($players); // 随机打乱顺序

while (count($players) > 1) {
    $winners = [];
    for ($i = 0; $i < count($players); $i += 2) {
        $player1 = $players[$i];
        $player2 = $players[$i + 1] ?? null;

        if ($player2) {
            echo "比赛: $player1 vs $player2\n";
            $winner = rand(0, 1) ? $player1 : $player2; // 模拟随机胜负
            $winners[] = $winner;
            echo "胜者: $winner\n\n";
        } else {
            $winners[] = $player1; // 轮空直接晋级
        }
    }
    $players = $winners;
}

echo "冠军是: " . $players[0];

处理轮空情况

当参赛人数不是2的幂次方时，需要处理轮空：

function generateBrackets($players) {
    $totalRounds = ceil(log(count($players), 2));
    $idealSize = pow(2, $totalRounds);
    $byes = $idealSize - count($players);

    $brackets = [];
    $round = 1;
    $currentPlayers = $players;

    while (count($currentPlayers) > 1) {
        $nextRound = [];
        $matches = [];

        // 处理轮空
        if ($round == 1 && $byes > 0) {
            $byedPlayers = array_slice($currentPlayers, 0, $byes);
            $currentPlayers = array_merge(
                $byedPlayers,
                array_slice($currentPlayers, $byes)
            );
        }

        // 生成比赛
        for ($i = 0; $i < count($currentPlayers); $i += 2) {
            $player1 = $currentPlayers[$i];
            $player2 = $currentPlayers[$i + 1] ?? null;

            if ($player2) {
                $match = "$player1 vs $player2";
                $winner = rand(0, 1) ? $player1 : $player2;
                $matches[] = $match;
                $nextRound[] = $winner;
            } else {
                $nextRound[] = $player1;
            }
        }

        $brackets["第{$round}轮"] = $matches;
        $currentPlayers = $nextRound;
        $round++;
    }

    return [
        'brackets' => $brackets,
        'champion' => $currentPlayers[0]
    ];
}

$result = generateBrackets(['A', 'B', 'C', 'D', 'E', 'F', 'G']);
print_r($result);

数据库存储赛果

对于更复杂的比赛系统，可以使用数据库存储比赛结果：

// 数据库表结构示例
/*
CREATE TABLE tournaments (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(255)
);

CREATE TABLE matches (
    id INT AUTO_INCREMENT PRIMARY KEY,
    tournament_id INT,
    round INT,
    player1_id INT,
    player2_id INT,
    winner_id INT,
    FOREIGN KEY (tournament_id) REFERENCES tournaments(id)
);
*/

// 插入比赛记录示例
function recordMatchResult($db, $tournamentId, $round, $player1, $player2, $winner) {
    $stmt = $db->prepare("INSERT INTO matches (tournament_id, round, player1_id, player2_id, winner_id) VALUES (?, ?, ?, ?, ?)");
    $stmt->execute([$tournamentId, $round, $player1, $player2, $winner]);
}

// 查询某轮比赛
function getRoundMatches($db, $tournamentId, $round) {
    $stmt = $db->prepare("SELECT * FROM matches WHERE tournament_id = ? AND round = ?");
    $stmt->execute([$tournamentId, $round]);
    return $stmt->fetchAll(PDO::FETCH_ASSOC);
}

可视化对阵表

使用HTML输出可视化的对阵表：

function renderBracket($players) {
    $rounds = [];
    $currentRound = $players;

    while (count($currentRound) > 1) {
        $nextRound = [];
        $matches = [];

        for ($i = 0; $i < count($currentRound); $i += 2) {
            $player1 = $currentRound[$i];
            $player2 = $currentRound[$i + 1] ?? '轮空';
            $winner = $player2 == '轮空' ? $player1 : (rand(0, 1) ? $player1 : $player2);

            $matches[] = [
                'players' => [$player1, $player2],
                'winner' => $winner
            ];
            $nextRound[] = $winner;
        }

        $rounds[] = $matches;
        $currentRound = $nextRound;
    }

    echo '<div style="display: flex; gap: 20px;">';
    foreach ($rounds as $roundNum => $matches) {
        echo '<div style="border: 1px solid #ccc; padding: 10px;">';
        echo "<h3>第" . ($roundNum + 1) . "轮</h3>";

        foreach ($matches as $match) {
            echo '<div style="margin-bottom: 10px; padding: 5px; background: #f5f5f5;">';
            echo "{$match['players'][0]} vs " . ($match['players'][1] ?? '轮空') . "<br>";
            echo "<strong>胜者: {$match['winner']}</strong>";
            echo '</div>';
        }

        echo '</div>';
    }
    echo '</div>';

    echo "<h2>冠军: {$currentRound[0]}</h2>";
}

renderBracket(['选手A', '选手B', '选手C', '选手D', '选手E', '选手F']);

这些方法提供了从简单到复杂的单淘汰赛制实现方案，可以根据实际需求选择适合的方式或组合使用。