PHP combine two seperate conflicting date ranges into unique pairs

Question

Set one:

1. 2014-04-05 To 2014-06-27
2. 2014-06-28 To 2014-10-19

Set two:

1. 2014-04-05 To 2014-05-02
2. 2014-05-03 To 2014

Answer 1

Here is my solution:

'2014-04-05','e'=>'2014-06-27'),
    array('s'=>'2014-06-28','e'=>'2014-10-19')
);
$array2 = array(
    array('s'=>'2014-04-05','e'=>'2014-05-02'),
    array('s'=>'2014-05-03','e'=>'2014-05-31'),
    array('s'=>'2014-06-01','e'=>'2014-10-19')
);

//merge arrays together
$merged_array = array_merge($array1,$array2);

//filter out duplicate start dates
$filtered_array = array();
foreach($merged_array as $k=>$v){
    if(!isset($filtered_array[ $v['s'] ] )){
        $filtered_array[ $v['s'] ] = $v;
    }

    //if the end date is before the currently saved end date (for this start date) then use it
    if( strtotime($v['e']) < strtotime($filtered_array[ $v['s'] ]['e']) ){
        $filtered_array[ $v['s'] ] = $v;
    }
}

//reset the array to zero based
$filtered_array = array_values($filtered_array);

//sort the array by start date
$tmp = array();
foreach($filtered_array as $k=>$v){
    $tmp[$k] = $v['s'];
}

array_multisort($tmp,SORT_ASC,$filtered_array);

//end date overlap checking
foreach($filtered_array as $k=>$v){
    //if the end date is after (or equal to) the "next" start date, then make that end date the "yesterday" of the next start date
    if( isset($filtered_array[$k+1]['s']) && strtotime($v['e']) >= strtotime($filtered_array[$k+1]['s'])  ){
        $yesterday = strtotime($filtered_array[$k+1]['s']) - 1;
        $yesterday = date("Y-m-d",$yesterday);
        $filtered_array[$k]['e'] = $yesterday;
    }
}

echo '
',print_r($filtered_array),'
';

/*
Array
(
    [0] => Array
        (
            [s] => 2014-04-05
            [e] => 2014-05-02
        )

    [1] => Array
        (
            [s] => 2014-05-03
            [e] => 2014-05-31
        )

    [2] => Array
        (
            [s] => 2014-06-01
            [e] => 2014-06-27
        )

    [3] => Array
        (
            [s] => 2014-06-28
            [e] => 2014-10-19
        )

)
*/