[模板]序列自动机

 仅作整理

struct substr
{
	vector <int> st[256];

	void init(char *x, int len)
	{
		for(int i = 0; i < len; ++i)
		{
			st[x[i]].push_back(i);
		}
	}
	
	bool isub(char *x, int len)
	{
		int now = -1;
		for(int i = 0; i < len; ++i)
		{
			auto it = upper_bound(st[x[i]].begin(), st[x[i]] .end(), now);
			if(it == st[x[i]].end())
				return false;
			else
				now = * it;;
		}
		return true;
	}
};

//序列自动机   
char arr[MAXN] = {0};  
char word[MAXN];  
struct substr  
{  
    struct node { int nex[26]; }pre[MAXN];  
    int cod[26];  
    void init(char *x)  
    {  
        for(int i = 0; i < 26; i++) cod[i] = -1;  
        int len = strlen(x);  
        for(int i = len - 1; i >= 0; i--)  
        {  
            for(int j = 0; j < 26; j++) pre[i].nex[j] = cod[j];  
            cod[arr[i] - 'a'] = i;  
        }  
    }  
    bool isub(char *word)  
    {  
        int len = strlen(word);  
        int nxt = -1;  
        for(int i = 0; i < len; i++)  
        {  
            int rx = word[i] - 'a';  
            if(i == 0) nxt = cod[rx];  
            else nxt = pre[nxt].nex[rx];  
            if(nxt == -1) return false;  
        }  
        return true;  
    }  
};