C++博客-syhd142-文章分类-字符串

HDU 3065 病毒侵袭持续中

Fucker — Mon, 10 Jan 2011 07:58:00 GMT

模板题

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <queue>

#define KIND 26
#define N 1005
#define M 2000005

struct node
{
    node *fail;
    node *next[KIND];
    int id;
    node ()
        {
            fail = NULL;
            id = 0;
            memset(next, 0, sizeof(next));
        }
};

char ch[M], key[N][55];
int count[N];

void insert(node *&root, char *ch, int num)
{
    node *p = root;
    int i = 0, t;
    while(ch[i])
    {
        t = ch[i] - 'A';
        if(!p->next[t]) p->next[t] = new node();
        p = p->next[t];
        i++;
    }
    p->id = num;
}

void AC(node *&root)
{
    std::queue<node *> q;
    q.push(root);
    while(!q.empty())
    {
        node *p = NULL;
        node *t = q.front();
        q.pop();
        for(int i = 0; i < KIND; i++)
        {
            if(t->next[i])
            {
                p = t->fail;
                while(p)
                {
                    if(p->next[i])
                    {
                        t->next[i]->fail = p->next[i];
                        break;
                    }
                    p = p->fail;
                }
                if(!p) t->next[i]->fail = root;
                q.push(t->next[i]);
           }
        }
    }
}

void query(node *&root, char *ch)
{
    int i = 0, t;
    node *p = root, *tmp;
    while(ch[i])
    {
        if(ch[i] > 'Z' || ch[i] < 'A')
        {
            p = root;
            i++;
            continue;
        }
        t = ch[i] - 'A';
        while(!p->next[t] && p != root) p = p->fail;
        p = p->next[t];
        if(!p) p = root;
        tmp = p;
        while(tmp != root)
        {
            count[tmp->id]++;
            tmp = tmp->fail;
        }
        i++;
    }
}

int main()
{
    int n;
    while(~scanf("%d", &n))
    {
        node *root = new node();
        memset(count, 0, sizeof(count));
        for(int i = 1; i <= n; i++)
        {
            scanf("%s", key[i]);
            insert(root, key[i], i);
        }
        AC(root);
        scanf("%s", ch);
        query(root, ch);
        for(int i = 1; i <= n; i++)
        {
            if(count[i])
            {
                printf("%s: %d\n", key[i], count[i]);
            }
        }
    }
    return 0;
}

Fucker 2011-01-10 15:58 发表评论

HDU 2896 病毒侵袭

Fucker — Sun, 09 Jan 2011 16:11:00 GMT

模板题

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;

#define KIND 128
#define M 10010

struct node
{
    node *fail;
    node *next[KIND];
    int id;
    node ()
        {
            fail = NULL;
            id = 0;
            memset(next, 0, sizeof(next));
        }
};

char ch[M];
queue<node *> q;
vector<int> g;

void insert(node *&root, char *ch, int id)
{
    node *p = root;
    int i = 0, t;
    while(ch[i])
    {
        t = ch[i] - 31;
        if(!p->next[t]) p->next[t] = new node();
        p = p->next[t];
        i++;
    }
    p->id = id;
}

void AC(node *&root)
{
    q.push(root);
    while(!q.empty())
    {
        node *p = NULL;
        node *t = q.front();
        q.pop();
        for(int i = 0; i < KIND; i++)
        {
            if(t->next[i])
            {
                p = t->fail;
                while(p)
                {
                    if(p->next[i])
                    {
                        t->next[i]->fail = p->next[i];
                        break;
                    }
                    p = p->fail;
                }
                if(!p) t->next[i]->fail = root;
                q.push(t->next[i]);
           }
        }
    }
}

bool query(node *&root, char *ch, int count)
{
    g.clear();
    int i = 0, t, top = 0, flag = 0;
    node *p = root, *tmp;
    while(ch[i])
    {
        t = ch[i] - 31;
        while(!p->next[t] && p != root) p = p->fail;
        p = p->next[t];
        if(!p) p = root;
        tmp = p;
        while(tmp != root && tmp->id)
        {
            flag = 1;
            g.push_back(tmp->id);
            tmp = tmp->fail;
        }
        i++;
    }
    if(!flag) return false;
    sort(g.begin(), g.end());
    printf("web %d:", count);
    printf(" %d", g[0]);
    for(int i = 1; i < g.size(); i++)
    {
        if(g[i] != g[i - 1])
        printf(" %d", g[i]);
    }
    printf("\n");
    return true;
}

int main()
{
    int n, total;
    while(~scanf("%d", &n))
    {
        node *root = new node();
        total = 0;
        for(int i = 0; i < n; i++)
        {
            scanf("%s", ch);
            insert(root, ch, i + 1);
        }
        AC(root);
        scanf("%d", &n);
        for(int i = 0; i < n; i++)
        {
            scanf("%s", ch);
            if(query(root, ch, i + 1)) total++;
        }
        printf("total: %d\n", total);
    }
    return 0;
}

Fucker 2011-01-10 00:11 发表评论

HDU 2222 Keywords Search

Fucker — Wed, 05 Jan 2011 09:38:00 GMT

由于论文的需要，看了一下AC自动机的原理，感觉就是trie树+kmp，这两个单独都写过，

但是合在一起还真没写过，参照网上的代码写了一个HDU上的题目，水的很，入门级别的。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define N 500005
#define KIND 26

struct node
{
    node *fail;
    node *next[KIND];
    int count;
    node()
        {
            fail = NULL;
            count = 0;
            memset(next, 0, sizeof(next));
        }
}*queue[N];

void insert(node *root, char *str)
{
    int i = 0, index;
    node *p = root;
    while(str[i])
    {
        index = str[i] - 'a';
        if(p->next[index] == NULL) p->next[index] = new node();
        p = p->next[index];
        i++;
    }
    p->count++;
}

void build(node *root)
{
    int front = 0, rear = 0;
    root->fail = NULL;
    queue[rear++] = root;
    while(front < rear)
    {
        node *tmp = queue[front++];
        node *p = NULL;
        for(int i = 0; i < KIND; i++)
        {
            if(tmp->next[i])
            {
                p = tmp->fail;
                while(p)
                {
                    if(p->next[i])
                    {
                        tmp->next[i]->fail = p->next[i];
                        break;
                    }
                    p = p->fail;
                }
                if(!p) tmp->next[i]->fail = root;
                queue[rear++] = tmp->next[i];
            }
        }
    }
}

char str[1000005];

int query(node *root)
{
    int i = 0, ans = 0, index;
    node *p = root, *tmp;
    while(str[i])
    {
        index = str[i] - 'a';
        while(p->next[index] == NULL && p != root) p = p->fail;
        p = p->next[index];
        if(!p) p = root;
        tmp = p;
        while(tmp != root)
        {
            ans += tmp->count;
            tmp->count = 0;
            tmp = tmp->fail;
        }
        i++;
    }
    return ans;
}

int main()
{
    int t, nkey, ans;
    char key[100];
    scanf("%d", &t);
    while(t--)
    {
        node *root = new node();
        scanf("%d", &nkey);
        for(int i = 0; i < nkey; i++)
        {
            scanf("%s", key);
            insert(root, key);
        }
        build(root);
        scanf("%s", str);
        ans = query(root);
        printf("%d\n", ans);
    }
    return 0;
}

Fucker 2011-01-05 17:38 发表评论

UVA 417 Word Index

Fucker — Wed, 06 Oct 2010 11:40:00 GMT

题目很简单，生成字母顺序的时候不会弄，代码能力还是不行。

#include <stdio.h>
#include <string>
#include <map>
using namespace std;

char word[27] = "abcdefghijklmnopqrstuvwxyz";
bool mk[27];
map<string, int> hash;
int num;

void build(int pos, int deep)
{
    if(!deep)
    {
        num++;
        char tmp[6];
        int len = 0;
        for(int i = 0; i < 26; i++)
        {
            if(mk[i]) tmp[len++] = word[i];
        }
        tmp[len] = 0;
    //    printf("%s\n", tmp);
    //    system("pause");
        hash[(string)tmp] = num;
        return;
    }
    if(pos >= 26) return;
    mk[pos] = 1;
    build(pos + 1, deep - 1);
    mk[pos] = 0;
    build(pos + 1, deep);
}

int main()
{
    num = 0;
    for(int i = 1; i < 6; i++) build(0, i);
    char data[6];
    while(gets(data)) printf("%d\n", hash[data]);
    return 0;
}

Fucker 2010-10-06 19:40 发表评论

UVA 10391 Compound Words

Fucker — Tue, 06 Jul 2010 16:33:00 GMT

题意：给定一个字典，要你判断其中的任意两个单词是否可以组成另一个单词。

解法：trie树，记录所有的单词，然后再对每个档次枚举分隔点。神奇的是我释放内存就RE，不释放就A了。没搞懂。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define N 50005
#define KIND 26

struct TreeNode
{
    int count;
    TreeNode *next[KIND];
    TreeNode()
    {
        count = 0;
        memset(next, 0, sizeof(next));
    }
}*root;

char data[N][105], data1[105], data2[105];

void Insert(char *s)
{
    TreeNode *r = root;
    for(; *s; s++)
    {
        int t = (*s) - 'a';
        if(NULL == r->next[t])
        {
            r->next[t] = new TreeNode();
        }
        r = r->next[t];
    }
    r->count = 1;
}

bool Find(char *s)
{
    int count = 0;
    TreeNode *r = root;
    for(; *s; s++)
    {
        int t = (*s) - 'a';
        if(r->next[t] == NULL) return false;
        r = r->next[t];
    }
    if(r->count) return true;
    return false;
}

void Release(TreeNode *p)
{
    for(int i = 0; i < KIND; i++)
    {
        if(p->next[i]) Release(p);
    }
    delete p;
}

int main()
{
    int n = 0;
    root = new TreeNode();
    while(scanf("%s", data[n]) != EOF)
    {
        Insert(data[n]);
        n++;
    }
    for(int i = 0; i < n; i++)
    {
        int l = strlen(data[i]);
        for(int j = 1; j < l; j++)
        {
            int k;
            for(k = 0; k < j; k++)
                data1[k] = data[i][k];
            data1[k] = '\0';
            for(k = j; k < l; k++)
                data2[k - j] = data[i][k];
            data2[k - j] = '\0';
        //    strncpy(data1, data[i], j);
        //    strncpy(data2, data[i] + j, l - j + 1);
        //    puts(data1);puts(data2);
            if(Find(data1) && Find(data2))
            {
                puts(data[i]);
                break;
            }
        }
    }
    //Release(root);
    return 0;
}

Fucker 2010-07-07 00:33 发表评论

PKU 3630 Phone List

Fucker — Sun, 04 Jul 2010 14:15:00 GMT

题意：给定n个长度不超过10的电话号码，求是否有电话号码是另一个的前缀。

解法：Trie树，代码能力直线下降啊。。这么简单的好写这么久。

#include <stdio.h>
#include <string.h>

#define N 10005
#define KIND 10

struct TreeNode
{
    TreeNode *next[KIND];
}table[N * 10], root;

char data[N][15];
int sp;

void Insert(char *data)
{
    TreeNode *r = &root;
    for(; *data; data++)
    {
        int t = *data - '0';
        if(NULL == r->next[t])
        {
            r->next[t] = &table[sp];
            memset(table[sp].next, 0, sizeof(table[sp].next));
            sp++;
        }
        r = r->next[t];
    }
}

bool Find(char *data)
{
    TreeNode *r = &root;
    for(; *data; data++)
    {
        int t = *data - '0';
        r = r->next[t];
    }
    for(int i = 0; i < KIND; i++)
        if(r->next[i]) return 1;
    return 0;
}

int main()
{
    int n, t;
    bool flag;
    scanf("%d", &t);
    while(t--)
    {
        scanf("%d", &n);
        memset(root.next, 0, sizeof(root.next));
        sp = 0;
        for(int i = 0; i < n; i++)
        {
            scanf("%s", &data[i]);
            Insert(data[i]);
        }
        flag = 1;
        for(int i = 0; i < n; i++)
        {
            if(Find(data[i]))
            {
                flag = 0;
                break;
            }
        }
        if(!flag) puts("NO");
        else puts("YES");
    }
    return 0;
}

Fucker 2010-07-04 22:15 发表评论