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这不是家庭作业：在处理 PHP 字符串差异和动态限制时遇到这种情况

给定一串n单词，如何在m不改变单词序列的情况下将它们分成组？

Example 1:
String: "My name is SparKot"
Groups: 2 (string is split in to two strings)

Possible groups will be:
('My', 'name is SparKot'), 
('My name', 'is SparKot'),
('My name is', 'SparKot')

用相同的字符串

Example 2:
String: "My name is SparKot"
Groups: 3 (string will be split in to three strings)

Possible groups will be:
('My', 'name', 'is SparKot'),
('My', 'name is', 'SparKot'),
('My name', 'is', 'SparKot')

我的 PHP 函数（）没有方向（假设返回多维组）：

function get_possible_groups ($orgWords, $groupCount, &$status) {

    $words = explode (' ', $orgWords);
    $wordCount = count($words);

    if ($wordCount < $groupCount) {
        $status = -1;
        return;
    } else if ($wordCount === $groupCount) {
        $status = 0;
        return (array_chunk($words, 1));
    }

    for ($idx =0; $idx < $wordCount; $idx) {
        for ($jdx =0; $jdx < $groupCount; $jdx++) {

        }
    }
//  append all arrays to form multidimension array
//  return groupings[][] array
}
$status =0;

$groupings = get_possible_groups('My name is SparKot', 4, $status);

var_dump($groupings);

对于上面的 example-2 函数应该返回：

$groupings = array (
        array ('My', 'name', 'is SparKot'),
        array ('My', 'name is', 'SparKot'),
        array ('My name', 'is', 'SparKot'));

任何解决此问题的提示将不胜感激。

进步：

  • 案例：当wordCount = groupCount[解决]
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1 回答 1

6

好的，所以，我花了很长时间，但我想我设法做到了这一点。老实说，我真的很自豪，因为我通常不擅长算法。无论如何，我们开始：

function getPossibleGroups($string, $groups) {
    $words = explode(' ', $string);
    $wordCount = count($words);

    if ($groups === 1) {
        return array(array($string));
    } elseif ($groups > $wordCount) {
        return null;
    } elseif ($groups === $wordCount) {
        return array($words);
    }

    $results = array();
    // We get every possible result for the first group
    for ($i = 1; $i <= $wordCount - $groups + 1; $i++) {
        $firstGroup = implode(' ', array_slice($words, 0, $i));

        // Recursively get all posible results for the other groups
        $otherGroups = getPossibleGroups(implode(' ', array_slice($words, $i)), $groups - 1);

        // Merge both things
        $allGroups = array_map(function($v) use ($firstGroup) {
            return array_merge(array($firstGroup), $v);
        }, $otherGroups);

        // Add that to the results variable
        $results = array_merge($results, $allGroups);
    }

    return $results;
}
于 2013-02-28T22:02:59.637 回答