HP implementation calculates the number of weeks in a year and returns the start time and end time of a week (optional return timestamp or date)

function getWeekStartAndEnd ($year,$week=1) {
 header("Content-type:text/html;charset=utf-8");
 date_default_timezone_set("Asia/Shanghai");
 $year = (int)$year;
 $week = (int)$week;
 //Calculate the total number of weeks in this year based on the given year
 $date = new DateTime;
 $date->setISODate($year, 53);
 $weeks = max($date->format("W"),52);
 //If the given week number is greater than the total number of weeks or less than or equal to 0
 if($week>$weeks || $week< =0){
 return false;
 }
 //If the number of weeks is less than 10
 if($week<10){
 $week = '0'.$week;
 }
 //The start and end timestamps of the current week
 $ timestamp['start'] = strtotime($year.'W'.$week);
 $timestamp['end'] = strtotime('+1 week -1 day',$timestamp['start']);
 //Start and end dates of the current week
 $timeymd['start'] = date("Y-m-d",$timestamp['start']);
 $timeymd['end'] = date("Y-m-d",$timestamp['end ']);
 //Return the starting timestamp
 return $timestamp;
 //Return the date format
 //return $timeymd;
}

Optional, one week, how many