病毒侵袭持续中 HDU

题目链接

题意：n个模式串，一个待匹配串，求求每个模式串在待匹配串中出现次数。

思路：记录模式串尾端，然后遍历统计。

#include <bits/stdc++.h>
using namespace std;
const int N = 50*1010;
int n;
char a[1010][60];
namespace AC {
int tr[N][130], tot;
int  fail[N],e[N];
int v[N];
int val[1010]; 
void insert(char *s,int w) {
  int u = 0;
  for (int i = 1; s[i]; i++) {
    if (!tr[u][s[i]]) tr[u][s[i]] = ++tot;
    u = tr[u][s[i]];
  }
  e[u]++;
  v[u]=w;
}
queue<int> q;
void build() {
  for (int i = 0; i < 130; i++)
    if (tr[0][i]) q.push(tr[0][i]);
  while (q.size()) {
    int u = q.front();
    q.pop();
    for (int i = 0; i < 130; i++) {
      if (tr[u][i])
        fail[tr[u][i]] = tr[fail[u]][i], q.push(tr[u][i]);
      else
        tr[u][i] = tr[fail[u]][i];
    }
  }
}
int query(char *t) {
  int u = 0, res = 0;
  int k=0;
  memset(val,0,sizeof(val));
  for (int i = 1; t[i]; i++) {
    u = tr[u][t[i]];  // 转移
    for (int j = u; j && e[j] != 0; j = fail[j]) {
      if(v[j])
      {
          val[v[j]]++;
      }
    }
  }
      for(int i=1;i<=n;i++)
      {
          if(val[i])
          {
              printf("%s: %d
",a[i]+1,val[i]);
          }
      }
}
void init(){
    memset(tr,0,sizeof(tr));
    tot=0;
    memset(fail,0,sizeof(fail));
    memset(e,0,sizeof(e));
    
}
}  // namespace AC
char s[2000010];
int main() {
    int ans=0;
  while(scanf("%d", &n)!=EOF){
      AC::init();
  for (int i = 1; i <= n; i++) scanf("%s", a[i] + 1), AC::insert(a[i],i);
  int t;
  AC::build();
  scanf("%s", s + 1);
  AC::query(s);
    }
  return 0;
}