poj 2846 Repository

题目大意：给你n个字符串，然后给你m个子串，看这个子串在上面的多少个串中，出现过；

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=2846

本题可以在字典树上进行改进；

AC代码：

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include<cstdlib>
 using namespace std;
 const int  maxn = ;
 typedef struct node
 {
     int count;
     int id;
     node *next[maxn];
 }trie;
 void inser(trie *root,char *s,int id)
 {
     int i,index;
     trie *p = root;
     for(i = ;s[i];i++)
     {
         index = s[i]-'a';
         if(p->next[index] == NULL)
         {
             trie *temp= (trie *)malloc(sizeof(trie));
             for(int j=;j<maxn;j++)
             {
                 temp->next[j] = NULL;
             }
             temp->count = ;
             temp->id = -;
             p->next[index] = temp;
         }
         p=p->next[index];
         if(p->id != id)
         {
             p->id = id;
             p->count++;//统计每个出现的个数；
         }
     }
 }
 int search(trie *root,char *s)
 {
     trie *p=root;
     int i,index;
     for(i=;s[i];i++)
     {
         index = s[i]-'a';
         if(p->next[index] == NULL) return ;
           p=p->next[index];
     }
     return p->count;
 }
 int main(int argc, char *argv[])
 {
     int i,j;
     int n,m;
     char s[];
     trie *root = (trie *)malloc(sizeof(trie));//清理内存，初始化；
             for(i=;i<maxn;i++)
             {
                 root->next[i] = NULL;
             }
             root->count = ;
             root->id = -;
     root->count = ;
     root->id  = -;
     scanf("%d",&n);
     for(i =;i<n;i++)
     {

        scanf("%s",s);
         for(j =;j<strlen(s);j++)
         {
             inser(root,s+j,i);
         }
     }
     scanf("%d",&m);
     for(i=;i<m;i++)
     {
         scanf("%s",s);
         printf("%d\n",search(root,s));
     }
     return ;
 }

代码二：

 #include<cstdio>
 #include<iostream>
 #include<cstring>
 #include<cstdlib>
 using namespace std;
 struct node
 {
     int count, id;
     node *childs[];
     node(){
         id=-;
         count=;
         int i;
         for(i=; i<; i++)
             childs[i]=NULL;
     }
 };
 node *root=new node;
 node *current, *newnode;
 void insert(char *str, int d)
 {
     int i, m;
     current=root;
     for(i=; i<strlen(str); i++)
     {
         m=str[i]-'a';
         if(current->childs[m]!=NULL)
         {
             current=current->childs[m];
         }
         else{
             newnode=new node;
             current->childs[m]=newnode;
             current=newnode;
         }
         if(current->id!=d)
         {
             current->id=d;
             ++(current->count);
         }
     }
 }
 int search(char *str)
 {
     //printf("%s",str);
     int i, m;
     current=root;
     for(i=; i<strlen(str); i++)
     {
         m=str[i]-'a';
         if(current->childs[m]==NULL)
             return ;
         current=current->childs[m];
     }
     return current->count;
 }

 int main()
 {
     int i, t, s, k;
     char a[];
     scanf("%d",&t);
     s=;
     while(t--){
         scanf("%s",a);
         s++;
         for(i=; i<strlen(a); i++)
         insert(a+i, s);
     }
     scanf("%d",&k);
     while(k--){
         scanf("%s",a);
         printf("%d\n",search(a));
     }
     return ;
 }