30. 串联所有单词的子串

<?php
class Solution {
    /**
     * @param String $s
     * @param String[] $words
     * @return Integer[]
     */
    function findSubstring($s, $words) {
        $wordCount = count($words);
        $wordLen = strlen($words[0]);
        $matchLen = $wordCount * $wordLen;
        $map = [];
        $ret = [];
        if (!$s || !$words) {
            return $ret;
        }
        // 匹配字符串数量映射
        foreach ($words as $v) {
            if (isset($map[$v])) {
                $map[$v]++;
            } else {
                $map[$v] = 1;
            }
        }
        // 迭代原字符串，查找匹配字符
        for ($i = 0; $i < strlen($s) - $matchLen; $i++) {
            $consumeMap = $map;
            $iterationStr = substr($s, $i, $matchLen);
            // 当前已匹配字符长度
            $currentLen = 0;
            $j = 0;
            while ($j < $wordCount) {
                $element = substr($iterationStr, $wordLen * $j, $wordLen);
                $j++;
                if (!isset($consumeMap[$element]) || $consumeMap[$element] < 1) {
                    break;
                }
                $currentLen += $wordLen;
                $consumeMap[$element] = $consumeMap[$element] - 1;
            }
            if ($currentLen < $matchLen) {
                continue;
            }
            $ret[] = $i;
        }
        return $ret;
    }
}
$s = "barfoothefoobarman";
$words = ["foo","bar"];
$cls = new Solution();
$r = $cls->findSubstring($s, $words);
print_r($r);