PHP 确定多个（n）日期时间范围何时相互重叠

我正在努力解决以下问题：

这是一个日历程序，给定多个人的一组可用日期时间集，我需要找出每个人在 PHP 中可用的日期时间范围

可用性集：

p1: start: "2016-04-30 12:00", end: "2016-05-01 03:00"

p2: start: "2016-04-30 03:00", end: "2016-05-01 03:00"

p3: start: "2016-04-30 03:00", end: "2016-04-30 13:31"
    start: "2016-04-30 15:26", end: "2016-05-01 03:00"

我正在寻找一个可以调用的函数，它可以告诉我所有 (p) 人同时可用的日期时间范围。

在上面的例子中，答案应该是：

2016-04-30 12:00 -> 2016-04-30 13:31
2016-04-30 15:26 -> 2016-05-01 03:00

我确实找到了类似的问题和答案Datetime - 确定 R 中多个（n）日期时间范围是否相互重叠

但我不知道那是什么语言，并且无法翻译答案中的逻辑。

嗯，那很有趣。可能有一种比每分钟循环更优雅的方法，但我不知道 PHP 是否是适合它的语言。请注意，当前需要管理单独搜索的开始时间和结束时间，尽管根据可用班次计算它们相当简单。

<?php
$availability = [
    'Alex' => [
        [
            'start' => new DateTime('2016-04-30 12:00'),
            'end'   => new DateTime('2016-05-01 03:00'),
        ],
    ],

    'Ben' => [
        [
            'start' => new DateTime('2016-04-30 03:00'),
            'end'   => new DateTime('2016-05-01 03:00'),
        ],
    ],

    'Chris' => [
        [
            'start' => new DateTime('2016-04-30 03:00'),
            'end'   => new DateTime('2016-04-30 13:31')
        ],

        [
            'start' => new DateTime('2016-04-30 15:26'),
            'end'   => new DateTime('2016-05-01 03:00')
        ],
    ],
];

$start = new DateTime('2016-04-30 00:00');
$end   = new DateTime('2016-05-01 23:59');
$tick  = DateInterval::createFromDateString('1 minute');

$period = new DatePeriod($start, $tick, $end);

$overlaps = [];
$overlapStart = $overlapUntil = null;

foreach ($period as $minute)
{
    $peopleAvailable = 0;

    // Find out how many people are available for the current minute
    foreach ($availability as $name => $shifts)
    {
        foreach ($shifts as $shift)
        {
            if ($shift['start'] <= $minute && $shift['end'] >= $minute)
            {
                // If any shift matches, this person is available
                $peopleAvailable++;
                break;
            }
        }
    }

    // If everyone is available...
    if ($peopleAvailable == count($availability))
    {
        // ... either start a new period...
        if (!$overlapStart)
        {
            $overlapStart = $minute;
        }

        // ... or track an existing one
        else
        {
            $overlapUntil = $minute;
        }
    }

    // If not and we were previously in a period of overlap, end it
    elseif ($overlapStart)
    {
        $overlaps[] = [
            'start' => $overlapStart,
            'end'   => $overlapUntil,
        ];

        $overlapStart = null;
    }
}

foreach ($overlaps as $overlap)
{
    echo $overlap['start']->format('Y-m-d H:i:s'), ' -> ', $overlap['end']->format('Y-m-d H:i:s'), PHP_EOL;
}