PHP simple permutation and combination algorithm example sharing

This article mainly introduces the simple permutation and combination algorithm implemented in PHP, and analyzes the implementation and use techniques of the permutation and combination algorithm based on specific application examples. Friends in need can refer to it. I hope it can help everyone.

1. Question:

I give you a 40-pound watermelon and divide it among 3 people. How many ways are there to divide it?

2. PHP implementation code:

<?php
$aa = range(1,40);
$bb = array();
foreach($aa as $k=>$val){
  foreach($aa as $v){
    foreach($aa as $vl){
      $sum = $val+$v+$vl;
      if($sum == 40){
        $bb[$k][0] = $val;
        $bb[$k][1] = $v;
        $bb[$k][2] = $vl;
      }
    }
  }
}
echo &#39;<pre class="brush:php;toolbar:false">&#39;;
print_r($bb);
exit;
?>

The running results are as follows:

Array
(
  [0] => Array
    (
      [0] => 1
      [1] => 38
      [2] => 1
    )
  [1] => Array
    (
      [0] => 2
      [1] => 37
      [2] => 1
    )
  [2] => Array
    (
      [0] => 3
      [1] => 36
      [2] => 1
    )
  [3] => Array
    (
      [0] => 4
      [1] => 35
      [2] => 1
    )
  [4] => Array
    (
      [0] => 5
      [1] => 34
      [2] => 1
    )
  [5] => Array
    (
      [0] => 6
      [1] => 33
      [2] => 1
    )
  [6] => Array
    (
      [0] => 7
      [1] => 32
      [2] => 1
    )
  [7] => Array
    (
      [0] => 8
      [1] => 31
      [2] => 1
    )
  [8] => Array
    (
      [0] => 9
      [1] => 30
      [2] => 1
    )
  [9] => Array
    (
      [0] => 10
      [1] => 29
      [2] => 1
    )
  [10] => Array
    (
      [0] => 11
      [1] => 28
      [2] => 1
    )
  [11] => Array
    (
      [0] => 12
      [1] => 27
      [2] => 1
    )
  [12] => Array
    (
      [0] => 13
      [1] => 26
      [2] => 1
    )
  [13] => Array
    (
      [0] => 14
      [1] => 25
      [2] => 1
    )
  [14] => Array
    (
      [0] => 15
      [1] => 24
      [2] => 1
    )
  [15] => Array
    (
      [0] => 16
      [1] => 23
      [2] => 1
    )
  [16] => Array
    (
      [0] => 17
      [1] => 22
      [2] => 1
    )
  [17] => Array
    (
      [0] => 18
      [1] => 21
      [2] => 1
    )
  [18] => Array
    (
      [0] => 19
      [1] => 20
      [2] => 1
    )
  [19] => Array
    (
      [0] => 20
      [1] => 19
      [2] => 1
    )
  [20] => Array
    (
      [0] => 21
      [1] => 18
      [2] => 1
    )
  [21] => Array
    (
      [0] => 22
      [1] => 17
      [2] => 1
    )
  [22] => Array
    (
      [0] => 23
      [1] => 16
      [2] => 1
    )
  [23] => Array
    (
      [0] => 24
      [1] => 15
      [2] => 1
    )
  [24] => Array
    (
      [0] => 25
      [1] => 14
      [2] => 1
    )
  [25] => Array
    (
      [0] => 26
      [1] => 13
      [2] => 1
    )
  [26] => Array
    (
      [0] => 27
      [1] => 12
      [2] => 1
    )
  [27] => Array
    (
      [0] => 28
      [1] => 11
      [2] => 1
    )
  [28] => Array
    (
      [0] => 29
      [1] => 10
      [2] => 1
    )
  [29] => Array
    (
      [0] => 30
      [1] => 9
      [2] => 1
    )
  [30] => Array
    (
      [0] => 31
      [1] => 8
      [2] => 1
    )
  [31] => Array
    (
      [0] => 32
      [1] => 7
      [2] => 1
    )
  [32] => Array
    (
      [0] => 33
      [1] => 6
      [2] => 1
    )
  [33] => Array
    (
      [0] => 34
      [1] => 5
      [2] => 1
    )
  [34] => Array
    (
      [0] => 35
      [1] => 4
      [2] => 1
    )
  [35] => Array
    (
      [0] => 36
      [1] => 3
      [2] => 1
    )
  [36] => Array
    (
      [0] => 37
      [1] => 2
      [2] => 1
    )
  [37] => Array
    (
      [0] => 38
      [1] => 1
      [2] => 1
    )
)

Related recommendations:

JS full permutation and combination algorithm implementation method

Detailed explanation of the implementation process of PHP simple permutation and combination algorithm

A brief discussion on sample code sharing of PHP permutations

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