PHP implementation bitmap Bitmap sorting to find the intersection

December 16, 2014 17:15:09

Initializes a string of all 0 binary;

An array of unordered integers;

If the integer x is in this integer array, the x position of the binary string is 1;

The binary string is then read sequentially, and the bits of 1 are converted into integers, stored sequentially in the new set, which is ordered.

Sort code:

1     function Sort()2     {3         //var_dump (Php_int_max, php_int_size);4 //int 92233720368547758075 //int 86         $bitmap=Array_fill(0, 50, 0);//apply an array of shapes, 50 elements, initialized to integers 07         $int _bit_size= Php_int_size * 8;//The number of bits for each shaping in the $BITMAP (in this case int = 8*8 = 64bit; $bitmap array altogether 50*64 = 3,200 bit bits), which means that the integer set with a maximum value of less than or equal to 3200 is sorted8         $a=Array(1,4,3,50,34,60,100,88,200,150,300);//define an array of random order9 Ten //Scan each number in $ A to convert it to x*64 + y One         foreach($a  as $k=$v) { A             $shang=$v/$int _bit_size; -             $yushu=$v%$int _bit_size; -  the             $offset= 1 <<$yushu; -  -             $bitmap[$shang] =$bitmap[$shang] |$offset;//Place the bit position at 1 -         } +  -         //You can get the sorted array by reverting the bit bits in $bitmap to the integer output in turn +         $b=Array(); A         foreach($bitmap  as $k=$v) { at              for($i= 0;$i<$int _bit_size;$i++) { -                 $tmp= 1 <<$i; -                 $flag=$tmp&$bitmap[$k]; -  -                 //$b [] = $flag? $k * $int _bit_size + $i: false; -                 if($flag) { in                     $b[] =$k*$int _bit_size+$i; -                 } to             } +         } -  the         Var_dump($b);Exit; *     } $ //Browser output:Panax Notoginseng Array -0 = int 1 the1 = int 3 +2 = int 4 A3 = int 34 the4 = int 50 +5 = int 60 -6 = int 88 $7 = int 100 $8 = int 150 -9 = int 200 -Ten = 300 int

To find the intersection code:

 Public function Sort($a=Array())    {        //var_dump (Php_int_max, php_int_size); int 9223372036854775807//int 8        $bitmap=Array_fill(0, 50, 0);//apply an array of shapes, 50 elements, initialized to integers 0        $int _bit_size= Php_int_size * 8;//The number of bits per shaping in the $bitmap (in this case int = 8*8 = 64bit; $bitmap array altogether 50*64 = 3,200 bit bits)//$a = Array (1,4,3,50,34,60,100,88,200 , 150,300); Set a disorderly array//scan each number in $ A to convert it to x*64 + y        foreach($a  as $k=$v) {            $shang=$v/$int _bit_size; $yushu=$v%$int _bit_size; $offset= 1 <<$yushu; $bitmap[$shang] =$bitmap[$shang] |$offset;//Place the bit position at 1        }        return $bitmap; }     Public functionintersect () {$int _bit_size= Php_int_size * 8; $a=Array(1,4,3,50,34,60,100,88,200,150,300); $b=Array(1,5,3,50,34,55,100,87,222,150,300); $bit _a=$this-Sort($a); $bit _b=$this-Sort($b); $c=Array(); foreach($bit _a  as $k=$v) {            $c[$k] =$bit _a[$k] &$bit _b[$k]; Binary & Compute Intersection}$d=Array(); foreach($c  as $k=$v) {             for($i= 0;$i<$int _bit_size;$i++) {                $tmp= 1 <<$i; $flag=$tmp&$c[$k]; //$b [] = $flag? $k * $int _bit_size + $i: false;                if($flag) {                    $d[] =$k*$int _bit_size+$i; }            }        }        Var_dump($d);Exit; } Browser Output:Array0 = int 1 1 = int 3 2 = int 3 = int 4 = int 5 = int 6 + int 300

Reference:

http://kevinbest0702.blog.163.com/blog/static/85409746201291484128939/

Http://www.cnblogs.com/dolphin0520/archive/2011/10/19/2217369.html

PHP implementation bitmap Bitmap sorting to find the intersection