【leetcode】Substring with Concatenation of All Words

vector<int> findSubstring(string S, const vector<string> &L) {

	vector<int> re;
	if(S.size() == 0 || L.size() == 0)
		return re;

	unordered_map<string, int> total;
	unordered_map<string, int> has;
	int wordNum = L.size();
	int wordLen = L[0].size();
	int searchEnd = S.size() - wordLen * wordNum;

	for (int i = 0; i < wordNum; ++i)
	{
		total[L[i]]++;
	}
	for (int i = 0; i <= searchEnd; ++i)
	{
		int j = i;
		has.clear();
		int iword = 0;
		for (; iword < wordNum; ++iword)
		{
			string sub = S.substr(j, wordLen);
			//not in L
			if(total[sub] == 0)
				break;
			//in L, but redundancy
			if(++has[sub] > total[sub])
				break;
			j += wordLen;
		}
		if(iword == wordNum)
		{
			re.push_back(i);
		}
	}
	return re;
}

后记：