数组中所有可能的组合-递归? [英] All possible combinations in array - recursion?

问题描述

我有一个想不通的问题，希望有人能提供帮助.我认为可能必须通过递归和/或置换来解决，但是我对于(PHP)程序员来说还不够好.

I have a question that goes over my head, hope someone can help. I think it may have to be solved by recursion and/or permutations, but I am not good enough of a (PHP) programmer for that.

$map[] = array("0", "1", "2", "3");
$map[] = array("4", "5", "6", "7");
$map[] = array("8", "9", "10", "11");
$map[] = array("12", "13", "14", "15");
$map[] = array("16", "17", "18", "19");
$map[] = array("20", "21", "22", "23");

$ map数组的最大长度限制为"6".

The $map array is limited to a max length of "6".

我正在寻找一种方法来进行所有可能的组合.以下是一些有效的组合:

I am looking for a way to make all possible combinations. Here are a few VALID combinations:

示例1:

$map[] = array("0", "1", "2", "3", "4", "5", "6", "7");
$map[] = array("8", "9", "10", "11");
$map[] = array("12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", );
$map[] = array("23");

示例2:

$map[] = array("0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23");

示例3:

$map[] = array("0", "1");
$map[] = array("2", "3", "4", "5", "6", "7", "8");
$map[] = array("9", "10", "11");
$map[] = array("12");
$map[] = array("13", "14", "15", "16", "17", "18", "19", "20");
$map[] = array("21", "22", "23");

每个映射数组中的值必须按升序排列，例如这个例子是无效的:

The values in each of the map arrays have to be in ascending order, e.g. this example is INVALID:

$map[] = array("0", "1", "4");
$map[] = array("3", "5");
etc...

希望可以做到.

推荐答案

递归解决方案.

<?php
function combination($remaining, $current, $combinations) {
    $e = array_shift($remaining);
    $combinations[$current][] = $e;

    if(empty($remaining)) {
        print_r($combinations);
        return;
    }

    combination($remaining, $current, $combinations);
    // 6 Limit remove for all solutions
    if ($current < 6) {
        combination($remaining, $current + 1, $combinations);
    }
}


$remaining = range(0, 23);

combination($remaining, 0, array());

如果您想存储[0,23]的所有解决方案，那将是一段糟糕的时光.

If you want to store all solutions for [0,23] you're gonna have a bad time.

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