php时间段判断

<?php
function times(){

    ini_set('date.timezone','Asia/Shanghai');

    $time = date("Y-m-d H:i");

    /*5.1*/
    if($time>"2017-05-01 09:00" && $time<"2017-05-01 09:20"){
        return "in";
    }
    if($time>"2017-05-01 10:00" && $time<"2017-05-01 10:20"){
        return "in";
    }
    if($time>"2017-05-01 11:00" && $time<"2017-05-01 11:20"){
        return "in";
    }
    if($time>"2017-05-01 15:00" && $time<"2017-05-01 15:20"){
        return "in";
    }
    if($time>"2017-05-01 16:00" && $time<"2017-05-01 16:20"){
        return "in";
    }
    if($time>"2017-05-01 17:00" && $time<"2017-05-01 17:20"){
        return "in";
    }

    /*5.2*/
    if($time>"2017-05-02 09:00" && $time<"2017-05-02 09:20"){
        return "in";
    }
    if($time>"2017-05-02 10:00" && $time<"2017-05-02 10:20"){
        return "in";
    }
    if($time>"2017-05-02 11:00" && $time<"2017-05-02 11:20"){
        return "in";
    }
    if($time>"2017-05-02 15:00" && $time<"2017-05-02 15:20"){
        return "in";
    }
    if($time>"2017-05-02 16:00" && $time<"2017-05-02 16:20"){
        return "in";
    }
    if($time>"2017-05-02 17:00" && $time<"2017-05-02 17:20"){
        return "in";
    }

    /*5.3*/
    if($time>"2017-05-03 09:00" && $time<"2017-05-03 09:20"){
        return "in";
    }
    if($time>"2017-05-03 10:00" && $time<"2017-05-03 10:20"){
        return "in";
    }
    if($time>"2017-05-03 11:00" && $time<"2017-05-03 11:20"){
        return "in";
    }
    if($time>"2017-05-03 15:00" && $time<"2017-05-03 15:20"){
        return "in";
    }
    if($time>"2017-05-03 16:00" && $time<"2017-05-03 16:20"){
        return "in";
    }
    if($time>"2017-05-03 17:00" && $time<"2017-05-03 17:20"){
        return "in";
    }

    return "noin";

}
?>