解题思路：
判断是否有一个字符串是另一个字符串的前缀，直接用字典树搞。
#include <iostream>#include <cstring>#include <cstdlib>#include <cstdio>#include <algorithm>#include <cmath>#include <queue>#include <set>#include <stack>#include <map>#define LL long longusing namespace std;typedef struct Trie_Node{bool isword;struct Trie_Node *next[10];}Trie;void insert(Trie *root, char *word){Trie *p = root;int i = 0;while(word[i] != '\0'){if(p->next[word[i]-'0'] == NULL){Trie *temp = new Trie;temp->isword = false;for(int j=0;j<10;j++)temp->next[j] = NULL;p->next[word[i]-'0'] = temp;}p = p->next[word[i]-'0'];i++;}p->isword = true;}int Find(Trie *root, char *word){Trie *p = root;int i = 0;int c = 0;while(word[i] != '\0'){if(p->next[word[i] – '0'] == NULL)return 0;p = p->next[word[i]-'0'];if(p->isword) c++;i++;}return c;}void del(Trie *root){for(int i=0;i<10;i++){if(root->next[i] != NULL)del(root->next[i]);}free(root);}char s[10010][15];int main(){int T, N;scanf("%d", &T);while(T–){Trie *root = new Trie;root->isword = false;for(int i=0;i<10;i++)root->next[i] = NULL;scanf("%d", &N);for(int i=1;i<=N;i++){scanf("%s", s[i]);insert(root, s[i]);}bool ok = true;for(int i=1;i<=N;i++){if(Find(root,s[i]) > 1){ok = false;break;}}if(ok) printf("YES\n");else printf("NO\n");del(root);}return 0;}
，这一秒不放弃，下一秒就会有希望。
