詢問有多少個模式串出現在了文本串裏面。將模式串插入Trie樹中,然後跑一邊AC自動機統計一下就哦了。
獻上一份模板。
#include <cstdio>
#include <algorithm>
#include <iostream>
#include <queue>
#include <cstring>
using namespace std;
int cnt;
struct AC_Automata {
#define N 240005
#define M 26
int ch[N][M], sz;
int val[N], last[N], f[N], cc[N];
void clear() { sz = 1; memset(ch[0], 0, sizeof(ch[0])); }
int idx(char c) { return c-'a'; }
void insert(char s[], int v) {
int u = 0;
for (int i=0; s[i]; i++) {
int c = idx(s[i]);
if (!ch[u][c]) {
memset(ch[sz], 0, sizeof(ch[sz]));
val[sz] = cc[sz] = 0;
ch[u][c] = sz++;
}
u = ch[u][c];
}
cc[u]++;
val[u] = v;
}
void build() {
queue<int> q;
f[0] = 0;
for (int c=0; c<M; c++) {
int u = ch[0][c];
if (u) { f[u] = 0, q.push(u); last[u] = 0; }
}
while (!q.empty()) {
int r = q.front(); q.pop();
for (int c=0; c<M; c++) {
int u = ch[r][c];
if (!u) { ch[r][c] = ch[f[r]][c]; continue; }
q.push(u);
int v = f[r];
f[u] = ch[v][c];
last[u] = val[f[u]] ? f[u] : last[f[u]];
}
}
}
void find(char *s) {
int j = 0;
for (int i=0; s[i]; i++) {
int c = idx(s[i]);
j = ch[j][c];
//if (val[j]) print(j);
//else if (last[j]) print(last[j]);
if (cc[j]) print(j);
else if (last[j]) print(last[j]);
}
}
void print(int j) { //打印以結點j結尾的所有字符串
if (j) {
//printf("%d: %d\n", j, val[j]);
cnt += cc[j];
cc[j] = 0;
print(last[j]);
}
}
} ac;
char s[55], text[1000006];
int main() {
int n, T;
scanf("%d", &T);
while (T--) {
scanf("%d", &n);
ac.clear();
for (int i=1; i<=n; i++) {
scanf(" %s", s); ac.insert(s, i);
}
ac.build();
cnt = 0;
scanf(" %s", text);
ac.find(text);
printf("%d\n", cnt);
}
return 0;
}