PHP實現bitmap點陣圖排序求交集

 1     function sort()
 2     {
 3         // var_dump(PHP_INT_MAX, PHP_INT_SIZE);
 4         // int 9223372036854775807
 5         // int 8
 6         $bitmap = array_fill(0, 50, 0); //申請一個整形陣列, 50個元素, 初始化為整數0
 7         $int_bit_size = PHP_INT_SIZE * 8; //$bitmap中每個整形的二進位制位數 (本例中int = 8*8 = 64bit; $bitmap陣列一共50*64 = 3200個bit位),也就是說能為最大值小於等於3200的整數集合排序
 8         $a = array(1,4,3,50,34,60,100,88,200,150,300); //定義一個亂序的陣列
 9 
10         //掃描$a中的每一個數, 將其轉換為 x*64 + y
11         foreach ($a as $k => $v) {
12             $shang = $v / $int_bit_size;
13             $yushu = $v % $int_bit_size;
14 
15             $offset = 1 << $yushu;
16 
17             $bitmap[$shang] = $bitmap[$shang] | $offset;//將bit位置為1
18         }
19 
20         //將$bitmap中的bit位依次還原為整數輸出,即可得到排序後的陣列
21         $b = array();
22         foreach ($bitmap as $k => $v) {
23             for ($i = 0; $i < $int_bit_size; $i++) {
24                 $tmp = 1 << $i;
25                 $flag = $tmp & $bitmap[$k];
26 
27                 // $b[] = $flag ? $k * $int_bit_size + $i : false;
28                 if ($flag) {
29                     $b[] =  $k * $int_bit_size + $i;
30                 }
31             }
32         }
33 
34         var_dump($b);exit;
35     }
36 // 瀏覽器輸出:
37 array
38   0 => int 1
39   1 => int 3
40   2 => int 4
41   3 => int 34
42   4 => int 50
43   5 => int 60
44   6 => int 88
45   7 => int 100
46   8 => int 150
47   9 => int 200
48   10 => int 300

public function sort($a = array())
    {
        // var_dump(PHP_INT_MAX, PHP_INT_SIZE);
        // int 9223372036854775807
        // int 8
        $bitmap = array_fill(0, 50, 0); //申請一個整形陣列, 50個元素, 初始化為整數0
        $int_bit_size = PHP_INT_SIZE * 8; //$bitmap中每個整形的二進位制位數 (本例中int = 8*8 = 64bit; $bitmap陣列一共50*64 = 3200個bit位)
        // $a = array(1,4,3,50,34,60,100,88,200,150,300); //定一個亂序的陣列

        //掃描$a中的每一個數, 將其轉換為 x*64 + y
        foreach ($a as $k => $v) {
            $shang = $v / $int_bit_size;
            $yushu = $v % $int_bit_size;

            $offset = 1 << $yushu;

            $bitmap[$shang] = $bitmap[$shang] | $offset;//將bit位置為1
        }

        return $bitmap;
    }

    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]; //二進位制 & 計算求交集
        }

        $d = array();
        foreach ($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;

    }
瀏覽器輸出:
array
  0 => int 1
  1 => int 3
  2 => int 34
  3 => int 50
  4 => int 100
  5 => int 150
  6 => int 300