hdu 1251 统计难题

这是字典树的入门题，很经典，也很容易，代码比较简单易懂，所以我就不解释了。不会字典树的同学请先上网搜索相关知识～～～

/* THE PROGRAM IS MADE BY PYY *//*----------------------------------------------------------------------------//Copyright (c) 2011 panyanyany All rights reserved. URL : http://acm.hdu.edu.cn/showproblem.php?pid=1251 Name : 统计难题 Date : Thursday, May 5, 2011 Time Stage : 2 hours around Result:39105512011-05-05 01:45:27Accepted125193MS43784K1423 BC++pyyTest Data:Review:初级题目，果然一次就AC了……//----------------------------------------------------------------------------*/#include <iostream>#include <conio.h>#include <stdio.h>#include <string.h>using namespace std;struct node {int cnt;node *childs[26];node() { cnt = 0; memset(childs, 0, sizeof(childs)); }};node *root = new node;int i, j, k, index;node *current, *newnode;void insert( char * str ){current = root;for( i = 0; str[i] != '/0'; ++i ){index = str[i] - 'a';if( current->childs[index] != NULL ){current = current->childs[index];++current->cnt;}else {newnode = new node;++newnode->cnt;current->childs[index] = newnode;current = newnode;}}}int is_find( char *str ){current = root;for( i = 0; str[i] != '/0'; ++i ){index = str[i] - 'a';if( current->childs[index] == NULL )return 0;current = current->childs[index];}return current->cnt;}int main(){char str[20];while( gets(str), strcmp(str, "") )insert( str );while( gets(str) != NULL )printf( "%d/n", is_find(str) );return 0;}