正题

luogu 5357

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题目大意

给你若干单词和一个字符串，让你查询每个单词在字符串中出现的次数

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解题思路

AC自动机模板

先把单词丢进去，然后拿字符串去跑，每到一个点累计答案

因为数据较大，所以要先存起来，跑完后按照bfs的倒叙传递答案

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代码

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define ll long long
#define N 200021
using namespace std;
int n, w, hd, tl, d[N], v[N], a[N], b[N], nx[N], to[N][30];
char s[N], ss[N*10];
int insert(char* s)
{int n = strlen(s+1), now = 0;for (int i = 1; i <= n; ++i){int y = s[i] - 'a';if (!to[now][y]) to[now][y] = ++w;now = to[now][y];}return now;
}
void bfs()
{hd = tl = 0;for (int i = 0; i < 26; ++i)if (to[0][i]) d[++tl] = to[0][i];while(hd < tl){int h = d[++hd];for (int i = 0; i < 26; ++i)if (!to[h][i]) to[h][i] = to[nx[h]][i];else nx[to[h][i]] = to[nx[h]][i], d[++tl] = to[h][i];}return;
}
void ask(char* s)
{int n = strlen(s+1), now = 0;for (int i = 1; i <= n; ++i){int y = s[i]- 'a';now = to[now][y];b[now]++;//记录答案}return;
}
int main()
{scanf("%d", &n);for (int i = 1; i <= n; ++i){scanf("%s", s+1);v[i] = insert(s);}bfs();scanf("%s", ss+1);ask(ss);for (int i = tl; i > 0; --i)//传递答案{int x = d[i];a[x] = b[x];b[nx[x]] += b[x];}for (int i = 1; i <= n; ++i)printf("%d\n", a[v[i]]);return 0;
}