between_dates.php

<?php
/**
* @var $initial int
* @var $end int
* @var $startEvent int
* @var $endEvent int
*/
function eventIsBetween($inital, $end, $startEvent, $endEvent):bool{
  if ($startEvent > $end || $endEvent < $initial){
      return false
  }
  for($i=$initial;$i>=$end; $i++){
    if(isBetween($i, $initial, $end)){
      return true;
    }
  }
  return false;
}

/**
* @var $needle int
* @var $initial int
* @var $end int
*/      
function isBetween($needle, $initial, $end):bool
{
    return ($needle <= $end) && ($needle >= $initial);
}