zoj 3430 Detect the Virus(AC自动机)

题目连接：zoj 3430 Detect the Virus

题目大意：给定一个编码完的串，将每一个字符对应着表的数值转换成6位二进制，然后以8为一个数值，重新形成字符

串，判断给定询问串是否含有字符集中的串。

解题思路：主要是题意，逆编码部分注意，转换完了之后，可能有字符'\0'，所以不能用字符串的形式储存，要用int型

的数组。注意有相同串的可能。

#include <cstdio>
#include <cstring>
#include <queue>
#include <vector>
#include <iostream>
#include <algorithm>

using namespace std;

typedef long long ll;

const int maxn = 512 * 100;
const int sigma_size = 256;

struct Aho_Corasick {
int sz, g[maxn][sigma_size];
int tag[maxn], fail[maxn], last[maxn];
bool vis[520];
int jump[520];

void init();
int idx(char ch);
void insert(int* str, int k);
void getFail();
int match(int* str);
void put(int u);
}A;

inline int change(char ch) {
if (ch >= 'A' && ch <= 'Z')
return ch - 'A';
if (ch >= 'a' && ch <= 'z')
return ch - 'a' + 26;
if (ch >= '0' && ch <= '9')
return ch - '0' + 52;
if (ch == '+')
return 62;
return 63;
}

const int maxl = 5005;

char w[maxl];
int s[maxl * 2];

void input(int* s) {

scanf("%s", w);
s[0]=0;
int n = strlen(w);
while (n && w[n-1] == '=') n--;
w
= 0;
for(int i=0,len=0,x=0;w[i];++i){
len+=6,x=(x<<6)|change(w[i]);
if(len>=8){
s[++s[0]]=(x>>(len-8))&0xff;
len-=8;
}
}

/*
for(int i = 1; i <= s[0]; i++)
printf(" %d", s[i]);
printf("\n");
*/
}

int N, M;

int main () {
while (scanf("%d", &N) == 1) {
A.init();

for (int i = 1; i <= N; i++) {
input(s);
A.insert(s, i);
}
A.getFail();

scanf("%d", &M);
for (int i = 1; i <= M; i++) {
input(s);
printf("%d\n", A.match(s));
}
printf("\n");
}
return 0;
}

void Aho_Corasick::init() {
sz = 1;
tag[0] = 0;
memset(g[0], 0, sizeof(g[0]));
}

int Aho_Corasick::idx(char ch) {
return ch;
}

void Aho_Corasick::put(int u) {
int p = tag[u];
while (p && vis[p] == 0) {
vis[p] = 1;
p = jump[p];
}
if (last[u])
put(last[u]);
}

void Aho_Corasick::insert(int* str, int k) {
int u = 0;

for (int i = 1; i <= str[0]; i++) {
int v = str[i];
while (v >= sigma_size);
if (g[u][v] == 0) {
tag[sz] = 0;
memset(g[sz], 0, sizeof(g[sz]));
g[u][v] = sz++;
}
u = g[u][v];
}

jump[k] = tag[u];
tag[u] = k;
}

int Aho_Corasick::match(int* str) {
memset(vis, 0, sizeof(vis));
int u = 0;

for (int i = 1; i <= str[0]; i++) {
int v = str[i];
while (v >= sigma_size);
while (u && g[u][v] == 0)
u = fail[u];

u = g[u][v];

if (tag[u])
put(u);
else if (last[u])
put(last[u]);
}

int ret = 0;
for (int i = 1; i <= N; i++)
if (vis[i])
ret++;
return ret;
}

void Aho_Corasick::getFail() {
queue<int> que;

for (int i  = 0; i < sigma_size; i++) {
int u = g[0][i];
if (u) {
fail[u] = last[u] = 0;
que.push(u);
}
}

while (!que.empty()) {
int r = que.front();
que.pop();

for (int i = 0; i < sigma_size; i++) {
int u = g[r][i];

if (u == 0) {
g[r][i] = g[fail[r]][i];
continue;
}

que.push(u);
int v = fail[r];
while (v && g[v][i] == 0)
v = fail[v];

fail[u] = g[v][i];
last[u] = tag[fail[u]] ? fail[u] : last[fail[u]];
}
}
}