ZOJ 3430 Detect the Virus(AC自动机+解码)

超级传送门：http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3430

本题思路清晰，不过解码确实繁琐，看来自己代码能力还有待加强。

需要注意几个点：解码后的ASCII字符的范围是0~255，而且可能包含'\0'，不能用char来存，最好用int。

代码：

#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <queue>

#define STATIC_AC_MOTON

using namespace std;

typedef int Type;

const int char_count = 256;
const char base_char = 0;

typedef struct __node
{
    Type val;
    int node_data;
    int vis;
    struct __node* next[char_count];
    struct __node* parent;
    struct __node* prefix;
}
Node;

#ifdef DYNAMIC_AC_MOTON
Node* rt;
#endif

#ifdef STATIC_AC_MOTON
const int max_node_count = 512 * 64 + 10;
Node node[max_node_count];
Node* rt = &node[0];
int node_count = 1;
#endif

int text[8 * 2048 + 10];
char _str[2048 + 10];

void createTree(Node** root)
{
#ifdef DYNAMIC_AC_MOTON
    *root = (Node*)malloc(sizeof(Node));
#endif
    (*root)->val = 0;
    (*root)->parent = NULL;
    (*root)->prefix = NULL;
    (*root)->vis = 0;
    (*root)->node_data = base_char;
    for (int i = 0; i < char_count; i++)
        (*root)->next[i] = NULL;
}

void deleteTree(Node* root)
{
#ifdef DYNAMIC_AC_MOTON
    if (root == NULL)
        return;
    for (int i = 0; i < char_count; i++)
    {
        if (root->next[i] != NULL)
            deleteTree(root->next[i]);
    }
    free(root);
#endif
#ifdef STATIC_AC_MOTON
    node_count = 1;
#endif
}

void insert(Node** root, int* str, int n)
{
    for (int i = 0; i < n; i++)
    {
        if ((*root)->next[str[i] - base_char] == NULL)
        {
#ifdef DYNAMIC_AC_MOTON
            (*root)->next[str[i] - base_char] = (Node*)malloc(sizeof(Node));
#endif
#ifdef STATIC_AC_MOTON
            (*root)->next[str[i] - base_char] = &node[node_count++];
#endif

            (*root)->next[str[i] - base_char]->parent = *root;
            root = &((*root)->next[str[i] - base_char]);
            (*root)->val = 0;
            (*root)->vis = 0;

            for (int j = 0; j < char_count; j++)
                (*root)->next[j] = NULL;
        }
        else
            root = &((*root)->next[str[i] - base_char]);

        (*root)->node_data = str[i];

        if (i == n - 1)
            (*root)->val++;
    }
}

int query(Node* root, int* text, int n)
{
    int count = 0;

    Node* p = root;
    int pos = 0;

    do
    {
        while (p != NULL && pos < n)
        {
            Node* cnt = p;
            while (cnt != root && !cnt->vis)
            {
                cnt->vis = 1;
                count += cnt->val;
                cnt = cnt->prefix;
            }

            if (p->next[text[pos] - base_char] != NULL)
            {
                p = p->next[text[pos] - base_char];
                pos++;
            }
            else
                p = p->prefix;
        }

        if (p == NULL)
        {
            p = root;
            pos++;
        }
        if (pos == n)
        {
            Node* cnt = p;
            while (cnt != root && !cnt->vis)
            {
                cnt->vis = 1;
                count += cnt->val;
                cnt = cnt->prefix;
            }
        }
    }
    while (pos < n);

    return count;
}

void make_prefix_pointer(Node* root)
{
    queue<Node*> q;
    q.push(root);

    while (!q.empty())
    {
        Node* cnt = q.front();
        q.pop();

        for (int i = 0; i < char_count; i++)
        {
            if (cnt->next[i] != NULL)
                q.push(cnt->next[i]);
        }

        if (cnt == root)
        {
            cnt->prefix = NULL;
            continue;
        }

        if (cnt->parent == root)
        {
            cnt->prefix = root;
            continue;
        }

        Node* pre = cnt->parent->prefix;

        while (pre != NULL)
        {
            if (pre->next[cnt->node_data - base_char] != NULL)
            {
                cnt->prefix = pre->next[cnt->node_data - base_char];
                break;
            }
            else
                pre = pre->prefix;
        }

        if (pre == NULL)
            cnt->prefix = root;
    }
}

void clearVisFlag(Node* root)
{
#ifdef DYNAMIC_AC_MOTON
    if (root == NULL)
        return;
    for (int i = 0; i < char_count; i++)
        clearVisFlag(root->next[i]);
    root->vis = 0;
#endif
#ifdef STATIC_AC_MOTON
    for (int i = 0; i < node_count; i++)
        node[i].vis = 0;
#endif
}

int decodeBase64ToASCII(int* des, char* src)
{
    int len = strlen(src);
    int desIndex = 0;
    int incNum = 0;
    int zeroBitsCount = 0;
    int bits[6];

    for (int i = 0; i < len; i++)
    {
        if (src[i] >= 'A' && src[i] <= 'Z')
            incNum = src[i] - 'A';
        else if (src[i] >= 'a' && src[i] <= 'z')
            incNum = src[i] - 'a' + 26;
        else if (src[i] >= '0' && src[i] <= '9')
            incNum = src[i] - '0' + 52;
        else if (src[i] == '+')
            incNum = 62;
        else if (src[i] == '/')
            incNum = 63;
        else if (src[i] == '=')
        {
            zeroBitsCount = len - i;
            break;
        }

        for (int j = 0; j < 6; j++)
            bits[j] = 0;
        int cntBitIndex = 5;
        while (incNum)
        {
            bits[cntBitIndex--] = incNum % 2;
            incNum >>= 1;
        }

        for (int j = 0; j < 6; j++)
            des[desIndex + j] = bits[j] + '0';
        desIndex += 6;
    }
    desIndex -= zeroBitsCount << 1;

    for (int i = 0; i < desIndex; i += 8)
    {
        int val = 0;
        for (int j = 7; j >= 0; j--)
            val += (des[i + j] - '0') * (1 << (7 - j));
        des[i / 8] = val;
    }
    return desIndex / 8;
}

int main()
{
    int n, m;

    while (scanf("%d", &n) > 0)
    {
        createTree(&rt);
        for (int i = 0; i < n; i++)
        {
            scanf("%s", _str);
            int len = decodeBase64ToASCII(text, _str);
            insert(&rt, text, len);
        }
        make_prefix_pointer(rt);

        scanf("%d", &m);
        for (int i = 0; i < m; i++)
        {
            scanf("%s", _str);
            int len = decodeBase64ToASCII(text, _str);
            printf("%d\n", n ? query(rt, text, len) : 0);
            clearVisFlag(rt);
        }
        printf("\n");
        deleteTree(rt);
    }
    return 0;
}