假设我们有一个带有单词的字符串：
1 2 3 4 5
我想要三个词的所有组合，但顺序不能改变。字符串可以是 4 个单词到 7 个单词之间的任何长度。不会更长，因为会有太多的组合。因此，示例 1 2 3 4 5 的结果将是一个包含字符串的数组：
1 2 3
1 2 4
1 2 5
1 3 4
1 3 5
1 4 5
2 3 4
2 3 5
2 4 5
3 4 5
我已经考虑了一段时间了。一个想法是将其转换为数组，为单词数量生成二进制代码，如果它是 1，则它显示单词，否则它不会（因此您可以获得从 11100 到 00111 的任何内容）。但这可能不是最佳的。
在这种情况下，速度很重要，因为它必须在几分钟内完成数万次。
我使用了Vicky的答案并做了一些修改。我认为这将按照您想要的方式工作
function everyCombination($array) {
$tempcount = 3; //lenght of the combinations you want
$arrayCount = count($array);
$maxCombinations = pow($arrayCount, $arrayCount);
$returnArray = array();
$conversionArray = array();
foreach ($array as $key => $value) {
$conversionArray[base_convert($key, 10, $arrayCount)] = $value;
}
for ($i = 0; $i < $maxCombinations; $i++) {
$flag = 1;
$combination = base_convert($i, 10, $arrayCount);
$combination = str_pad($combination, $tempcount, "0", STR_PAD_LEFT);
$temp = strtr($combination, $conversionArray);
for($j = 0; $j < $tempcount-1; $j++){
if($temp[$j] >= $temp[$j+1] || $flag == 0)
$flag = 0;
else
$flag = 1;
}
if($flag && strlen($temp) == $tempcount)
$returnArray[] = $temp;
}
return $returnArray;
}
print_r(everyCombination(array(1,2,3,4)));
你可以这样做：
<?php
function everyCombination($array)
{
$arrayCount = count($array);
$resultArray = array();
$veryFinal = array();
$maxCombinations = pow($arrayCount, $arrayCount);
$returnArray = array();
$conversionArray = array();
foreach ($array as $key => $value) {
$conversionArray[base_convert($key, 10, $arrayCount)] = $value;
}
for ($i = 0; $i < $maxCombinations; $i++) {
$combination = base_convert($i, 10, $arrayCount);
$combination = str_pad($combination, $arrayCount, "0", STR_PAD_LEFT);
$returnArray[] = strtr($combination, $conversionArray);
}
$finalArray = array();
foreach ($returnArray as $sepArray) {
array_push($finalArray, array_unique(str_split($sepArray)));
}
foreach ($finalArray as $result) {
$temp = implode(",", $result);
if (count($result) == 3) {
array_push($resultArray, $temp);
}
}
$tempFinal = array_unique($resultArray);
foreach ($tempFinal as $final) {
array_push($veryFinal, $final);
}
return $veryFinal;
}
$res1 = (everyCombination(array(1, 2, 3, 4)));
$res2 = (everyCombination(array('a','b','c','d')));
var_dump($res1);
var_dump($res2);
它给出：
array (size=24)
0 => string '1,2,3' (length=5)
1 => string '1,2,4' (length=5)
2 => string '1,3,2' (length=5)
3 => string '1,3,4' (length=5)
4 => string '1,4,2' (length=5)
5 => string '1,4,3' (length=5)
6 => string '2,1,3' (length=5)
7 => string '2,1,4' (length=5)
8 => string '2,3,1' (length=5)
9 => string '2,3,4' (length=5)
10 => string '2,4,1' (length=5)
11 => string '2,4,3' (length=5)
12 => string '3,1,2' (length=5)
13 => string '3,1,4' (length=5)
14 => string '3,2,1' (length=5)
15 => string '3,2,4' (length=5)
16 => string '3,4,1' (length=5)
17 => string '3,4,2' (length=5)
18 => string '4,1,2' (length=5)
19 => string '4,1,3' (length=5)
20 => string '4,2,1' (length=5)
21 => string '4,2,3' (length=5)
22 => string '4,3,1' (length=5)
23 => string '4,3,2' (length=5)
array (size=24)
0 => string 'a,b,c' (length=5)
1 => string 'a,b,d' (length=5)
2 => string 'a,c,b' (length=5)
3 => string 'a,c,d' (length=5)
4 => string 'a,d,b' (length=5)
5 => string 'a,d,c' (length=5)
6 => string 'b,a,c' (length=5)
7 => string 'b,a,d' (length=5)
8 => string 'b,c,a' (length=5)
9 => string 'b,c,d' (length=5)
10 => string 'b,d,a' (length=5)
11 => string 'b,d,c' (length=5)
12 => string 'c,a,b' (length=5)
13 => string 'c,a,d' (length=5)
14 => string 'c,b,a' (length=5)
15 => string 'c,b,d' (length=5)
16 => string 'c,d,a' (length=5)
17 => string 'c,d,b' (length=5)
18 => string 'd,a,b' (length=5)
19 => string 'd,a,c' (length=5)
20 => string 'd,b,a' (length=5)
21 => string 'd,b,c' (length=5)
22 => string 'd,c,a' (length=5)
23 => string 'd,c,b' (length=5)