字典树(tire树)

#include<cstdio>
#include<cstring>
#include<iostream>

using namespace std;

struct node
{
    int next[26];
    int cnt;
    void init()
    {
        cnt=0;
        memset(next,-1,sizeof(next));
    }
}T[1000000];

int le;  //第几个字典序

void insert(char *s)
{
    int i=0,p=0;
    while(s[i])
    {
        int x=s[i]-'a';
        if(T[p].next[x]==-1)
        {
            T[le].init(); 
            T[p].next[x] = le++;
        }
        p=T[p].next[x];
        T[p].cnt++;
        i++;
    }
}
void query(char *s)
{
    int i=0,p=0;
    while(s[i])
    {
        int x=s[i]-'a';
        if(T[p].next[x]==-1)
        {
            puts("0");
            return ;
        }
        p=T[p].next[x];
        i++;
    }
    printf("%d\n",T[p].cnt);
}
int main()
{
    int n,m;
    char str[20];
    scanf("%d",&n);
    le=1;
    T[0].init();
    while(n--) {
        scanf("%s",str);
        insert(str);
    }
    scanf("%d",&m);
    while(m--) {
        scanf("%s",str);
        query(str);
    }
}

 

const int maxn = 6e5 + 20;
const int sigma_size = 3;
 
struct Node {
    int cnt;
    bool isEnd;
    Node *next[sigma_size];
} trie[maxn];
 
typedef Node Trie;
int cnt_node = 0;
 
void insert_Trie (char *str, Trie *root) {
    root -> cnt ++;
    if (str[0] == 0) {
        root -> isEnd = 1;
        return ;
    }
    if (root -> next[str[0] - 'a'] == 0) {
        cnt_node ++;
        root -> next[str[0] - 'a'] = trie + cnt_node;
        root -> isEnd = 0;
    }
    insert_Trie (str + 1, root -> next[str[0] - 'a']);
}