統計難題 hdu1251

   字典樹的純模板題。初學字典樹，紀念一下下

 

#include<iostream>#include<cstdio>#include<cstring>using namespace std;struct node{int count;//記錄當前單詞出現的次數node *next[26];};node *root;//根節點,不儲存資訊node * build_node()//建立節點{node *p=new node;for(int i=0;i<26;i++)p->next[i]=NULL;p->count=1;return p;}void build_tree(char *s)//建字典樹{int len=strlen(s);node *p=root;for(int i=0;i<len;i++){if(p->next[s[i]-'a']==NULL)//該字母未出現過，所以建立一個節點p->next[s[i]-'a']=build_node();elsep->next[s[i]-'a']->count++;p=p->next[s[i]-'a'];}}int query(char *s){int len=strlen(s);node *p=root;for(int i=0;i<len;i++){if(p->next[s[i]-'a']==NULL)return 0;p=p->next[s[i]-'a'];}return p->count;}int main(){char s[15];root=build_node();while(gets(s)){if(s[0]=='\0')break;build_tree(s);}while(gets(s)){printf("%d\n",query(s));}return 0;}