简单字典树练习

题目：http://acm.hdu.edu.cn/showproblem.php?pid=1251

 

这个相当简单就不解释了。

直接上代码。

 

#include "iostream"
#include "cstdio"
#include "cstring"
#include "string"
using namespace std;
typedef struct node{
    int Cross;
    struct node *next[26];
}node;
node *head;
void InitHead(){
    head = (node *)malloc(sizeof(node));
    head->Cross = 0;
    memset(head->next, NULL, sizeof(head->next)); 
}
void Build(char *word){
    node *p = head;
    int i, k, Len = strlen(word);
    for(i=0; i<Len; i++){
        k = word[i]-'a';
        if(p->next[k]==NULL){
            p->next[k] = (node*)malloc(sizeof(node));
            p->next[k]->Cross=1;
            memset(p->next[k]->next, NULL, sizeof(p->next[k]->next));
        }else{
            p->next[k]->Cross++;
        }
        p = p->next[k];
    }
}
int Find(char *pre){
    node *p = head;
    int i, k, Len = strlen(pre);
    for(i=0; i<Len; i++){
        k = pre[i]-'a';
        if(p->next[k]==NULL) return 0;
        p = p->next[k];
        if(i==Len-1){
            return p->Cross;
        }
    }
}
int main(){
    char word[15];
    InitHead();
    while(gets(word), strcmp(word, "")!=0){
        Build(word);
    }
    while(gets(word)){
        printf("%d\n",Find(word));
    }
}