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- <?php
- namespace App\Services;
- class CombinationService
- {
- public static function combination($arr, $num)
- {
- $r = array();
- $n = count($arr);
- if ($num <= 0 || $num > $n) {
- return $r;
- }
- for ($i = 0; $i < $n; $i++) {
- $t = array($arr[$i]);
- if ($num == 1) {
- $r[] = $t;
- } else {
- $b = array_slice($arr, $i + 1);
- $c = self::combination($b, $num - 1);
- foreach ($c as $v) {
- $r[] = array_merge($t, $v);
- }
- }
- }
- return $r;
- }
- public static function combinationALL($array, $level = -1, &$list = [])
- {
- for ($i = 0; $i < count($array); $i++) {
- if ($level < 0) {
-
- $list[][] = $array[$i];
- } else {
- $values = $array[$i];
-
- for ($k = 0; $k < $level; $k++) {
- $values .= '+' . $array[$i + $k + 1];
- }
- $j = 0;
-
- for ($n = ($i + $level + 1); $n < count($array); $n++) {
- $j++;
- $first = $values;
- $first .= '+' . $array[$n];
- $list[] = str2arr($first, '+');
- }
-
- if ($j == 1) {
- break;
- }
- }
- }
-
- if (($level + 2) < count($array)) {
- self::combinationALL($array, $level + 1, $list);
- }
- return $list;
- }
- }
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