给定一个数组:A、B、C、D,输出长度为N的组合,返回所有的组合的方式
<?php
/**
* 组合:数据集$list,组合的个数:$num
* @param $list
* @param $m
* @return []
*/
function arrangement($list, $num) {
$res = [];
$count = count($list);
if ($num <= 0 || $num > $count) {
return $res;
}
for ($i=0; $i<$count; $i++) {
$_list = $list;
$tmp = array_splice($_list, $i, 1);
if ($num == 1) {
$res[] = $tmp;
} else {
$temp = arrangement($_list, $num-1);
foreach ($temp as $v) {
$res[] = array_merge($tmp, $v);
}
}
}
return $res;
}
$list = ['A', 'C', 'E', 'G'];
print_r( arrangement($list , 4) );