《leetCode-php》列出 字符串 可以由一个字符串数组中的元素拼接而来的所有可能方式

Given a string s and a dictionary of words dict, add spaces in s to construct a sentence where each word is a valid dictionary word.
给定一个字符串s和单词字典dict，在s中添加空格来构造所有字都在字典中的句子。
Return all such possible sentences.
返回所有的句子
For example, given
s ="catsanddog",
dict =["cat", "cats", "and", "sand", "dog"].

A solution is["cats and dog", "cat sand dog"].

思路和前一题相同，使用动态规划

 array(''),
        );
        for ($i = 1; $i <= $sNum; $i ++) {
            for ($j = 0; $j < $i; $j ++) {
                if ($j == 0) {
                    $subS = substr($s, -1 * $i);
                } else {
                    $subS = substr($s, -1 * $i,-1 * $j);
                }
                if (in_array($subS, $dict) && isset($A[$j])) {
                    foreach ($A[$j] as $value) {
                        $A[$i][] = $subS.' '.$value;
                    }
                }
            }
        }
        return $A[$sNum];
    }
}
$str = 'helloiamame';
$dict = array(
    'hello','i','am','ame',
);
$objSolution = new Solution();
$ret = $objSolution->wordBreak($str, $dict);
print_r($ret);