hdu1251 字典树

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

char str[20];

struct node {

    node *next[27];
    int num;
};
node *root;

using namespace std;

void build(char *t) {

    node *p = root, *q;
    int len = strlen(t);
    for(int i = 0; i < len; i++) {

        int k = t[i] - 'a';
        if(p->next[k] == NULL) {

            q = (node*)malloc(sizeof(node));
            for(int j =0; j < 27; j++) {

                q->next[j] = NULL;
            }
            p->next[k] = q;
            p = p->next[k];
            p->num = 1;
        }else {

            p = p->next[k];
            p->num++;

        }
    }
}


int Find(char *t) {

    node *p = root;
    int len = strlen(t);
    int k;
    for(int i = 0; i < len; i++) {

        k = t[i] - 'a';
        if(p->next[k] == NULL) {
            return 0;

        }else {


            p = p->next[k];
        }
    }
    return p->num;
}

int main()
{
    root = (node*)malloc(sizeof(node));
    for(int i = 0; i < 27; i++) {

        root->next[i] = NULL;
    }
    root->num = 0;

    while(gets(str), strcmp(str, "")!= 0) {

       build(str);
    }

     while(scanf("%s", str) != EOF) {

       printf("%d\n", Find(str));
    }

    return 0;
}