多模式串字符串匹配模板题

总时间限制: 

1000ms

 

内存限制: 

65536kB

描述

给若干个模式串，以及若干个句子，判断每个句子里是否包含模式串。 句子和模式串都由小写字母组成

输入

第一行是整数n，表示有n个模式串 ( n <= 1000)
接下来n行每行一个模式串。每个模式串长度不超过20
接下来一行是整数m，表示有m个句子 (m <= 1000)
接下来m行，每行一个句子，每个句子长度不超过1000

输出

对每个句子，如果包含某个模式串，则输出 YES, 否则输出 NO

样例输入

3
abc
def
gh
2
abcd
ak

样例输出

YES
NO

#include <iostream>
#include <cstring>
#include <deque>
using namespace std;

const int maxN = 1005;
const int maxM = 1005;
const int LETTERS = 26;

struct CNode
{
    CNode *pChilds[LETTERS];
    CNode *pPrev;
    bool bBadNode;
    CNode(){
        memset(pChilds, 0, sizeof(pChilds));
        pPrev = NULL;
        bBadNode = false;
    }
}Tree[30000];

int N, M, nNodesCount;               /* N pattern strings and M sentences */
char patternStr[maxN];

void Insert(CNode* pRoot, char *s)
{
    for (int i = 0; s[i]; i++){
        if (!pRoot->pChilds[s[i] - 'a']) {
            pRoot->pChilds[s[i] - 'a'] = Tree + nNodesCount;
            nNodesCount++;
        }
        pRoot = pRoot->pChilds[s[i] - 'a'];
    }
    pRoot->bBadNode = true;
}

void BuildDfa()
{
    for (int i = 0; i < LETTERS; i++)
        Tree[0].pChilds[i] = Tree + 1;
    Tree[0].pPrev = NULL;
    Tree[1].pPrev = Tree;
    deque<CNode *> q;
    q.push_back(Tree + 1);
    while (!q.empty()) {
        CNode *pRoot = q.front();
        q.pop_front();
        for (int i = 0; i < LETTERS; i++) {
            CNode *p = pRoot->pChilds[i];
            if (p) {
                CNode *pPrev = pRoot->pPrev;
                while (!pPrev->pChilds[i])
                    pPrev = pPrev->pPrev;
                p->pPrev = pPrev->pChilds[i];
                if (p->pPrev->bBadNode)
                    p->bBadNode = true;
                q.push_back(p);
            }
        }
    }
}

bool SearchDfa(char *s)
{
    CNode *p = Tree + 1;
    for (int i = 0; s[i]; i++) {
        while (!p->pChilds[s[i] - 'a'])
            p = p->pPrev;
        p = p->pChilds[s[i] - 'a'];
        if (p->bBadNode) return true;
    }
    return false;
}

int main()
{
    char s[maxN];
    nNodesCount = 2;

    cin >> N;
    for (int i = 0; i < N; i++) {
        cin >> patternStr;
        Insert(Tree + 1, patternStr);
    }

    BuildDfa();

    cin >> M;
    for (int i = 0; i < M; i++){
        cin >> s;
        if (SearchDfa(s)) printf("YES
");
        else printf("NO
");
    }

    //system("pause");
    return 0;
}