The method of realizing bitmap bitmap sorting and intersection by PHP _php skill

This article illustrates the method of realizing the intersection of bitmap bitmap sorting by PHP. Share to everyone for your reference, specific as follows:

Initialization of a string of 0 binary;

An array of unordered integers existing in a sequence;

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

Then sequentially reads the binary string and converts the bits of 1 to integers, sorted into the new set, which is sorted.

Sort code:

function sort () {//Var_dump (Php_int_max, php_int_size); int 9223372036854775807//int 8 $bitmap = Array_fill (0, 50, 0); Apply for an orthopedic array, 50 elements, initialized to integer 0 $int _bit_size = php_int_size * 8; The number of bits for each shape in the $bitmap (in this case int = 8*8 = 64bit; $bitmap array is 50*64 = 3,200 bit bits), that is, it can be sorted for an integer set that has a maximum value of less than or equal to 3200 $a = array (1,4,3,50 , 34,60,100,88,200,150,300);
      Defines an ordered array//scan $a for each number, converting it to x*64 + y foreach ($a as $k => $v) {$shang = $v/$int _bit_size;
      $yushu = $v% $int _bit_size;
      $offset = 1 << $yushu; $bitmap [$shang] = $bitmap [$shang] |
    $offset///The bit position is 1}//The bit bit in the $bitmap is sequentially restored to the integer output, the sorted array $b = Array () is obtained;
        foreach ($bitmap as $k => $v) {for ($i = 0; $i < $int _bit_size; $i + +) {$tmp = 1 << $i;
        $flag = $tmp & $bitmap [$k]; $b [] = $flag?
        $k * $int _bit_size + $i: false;
        if ($flag) {$b [] = $k * $int _bit_size + $i;
}} var_dump ($b); exit;

 }

Browser output:

Array
0 => Int 1
1 => int 3
2 => int 4
3 => int 34
4 => int 50
5 => int 60
6 => int 88
7 => int 100
8 => int 150
9 => int 200
Ten => int 300

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 for an orthopedic array, 50 elements, initialized to integer 0 $int _bit_size = php_int_size * 8; The number of bits for each shape 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 sequence of arrays//scan each number in the $a, convert it to x*64 + y foreach ($a as $k => $v) {$shang = $v/$int _bit_size;
      $yushu = $v% $int _bit_size;
      $offset = 1 << $yushu; $bitmap [$shang] = $bitmap [$shang] |
  $offset//The bit position is 1} return $bitmap;
    The public function intersect () {$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:

Array
0 => Int 1
1 => int 3
2 => int 34
3 => int 50
4 => int 100
5 => int 150
6 => int 300

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