POJ 3630 Trie树

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题意：给你一系列互不相同的电话号码，若存在某个号码是其他某个号码的前缀，则输出不相容（NO), 否则输出相容（YES)。

#include <iostream>using namespace std;const int kind = 10;//代表字符种类，共10个，1,2,3,4,5,6,7,8,9,0.int cnt; //统计已经被占用的节点的gstruct Treenode{bool flag;/*标记是否为电话号码的最后一个数字，若是flag=1*/Treenode *next[kind];} node[100000];void Insert ( Treenode * &root, char *phnum ){Treenode *location = root;if ( location == NULL ){location = &node[cnt++];root = location;}int id, i = 0, len = strlen(phnum);while ( phnum[i] ){id = phnum[i] - '0';if ( location->next[id] == NULL )location->next[id] = &node[cnt++];if ( i == len-1 ) /*电话号码的最后一个数字*/location->next[id]->flag = true;++i;location = location->next[id];}}bool Search ( Treenode *root, char *phnum ) /*检测到不相容就返回true，否则返回false，不相容指的是某个已插入的号码是phnum的前缀，或者phnum是某个已插入号码的前缀*/{Treenode *location = root;if ( location == NULL ) return false;int id, i = 0;while ( phnum[i] ){id = phnum[i] - '0';if ( location->next[id] == NULL )return false;if ( location->next[id]->flag == true )              /*假设123已经插入，在检测12345时，发现3已经是某个号码的最后一个数字，则说明该号码是12345的前缀，找到不相容*/return true;++i;location = location->next[id];}return true;}int main(){int t, n, find;char phnum[10];Treenode *root;   scanf("%d",&t);while ( t-- ){cnt = find = 0; /*find标志是否检测到不相容，开始时肯定是相容的，则find=0*/root = NULL;memset(node,NULL,sizeof(node));scanf("%d",&n);while ( n-- ){scanf("%s",phnum);if ( !find )    find = Search ( root, phnum );if ( !find )Insert( root, phnum );}if ( find )printf("NO\n");elseprintf("YES\n");}return 0;}