Phone List
Time Limit: 3000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 7343 Accepted Submission(s): 2525
Problem Description
Given a list of phone numbers, determine if it is consistent in the sense that no number is the prefix of another. Let’s say the phone catalogue listed these numbers: 1.
Emergency 911 2. Alice 97 625 999 3. Bob 91 12 54 26 In this case, it’s not possible to call Bob, because the central would direct your call to the emergency line as soon
as you had dialled the first three digits of Bob’s phone number. So this list would not be consistent.
Input
The first line of input gives a single integer, 1 <= t <= 40, the number of test cases. Each test case starts with n, the number of phone numbers, on a separate line, 1 <= n
<= 10000. Then follows n lines with one unique phone number on each line. A phone number is a sequence of at most ten digits.
Output
For each test case, output “YES” if the list is consistent, or “NO” otherwise.
Sample Input
2
3
911
97625999
91125426
5
113
12340
123440
12345
98346
字典树递归算法：
1 #include <iostream> 2 #include <stdio.h> 3 #include <algorithm> 4 #include <string.h> 5 #include <math.h> 6 #include <vector> 7 #include <stack> 8 #include <map> 9 using namespace std; 10 #define ll long long int 11 #define INF 5100000 12 typedef struct node 13 { 14 struct node *next[10]; 15 int n; 16 bool end; 17 } trie; 18 trie *inti() 19 { 20 trie *t; 21 t=(trie *)malloc(sizeof(trie)); 22 t->end=0; 23 t->n=0; 24 for(int i=0; i<10; i++) t->next[i]=NULL; 25 return t; 26 } 27 int insert(trie *t,char a[]) 28 { 29 30 if(t->end)return 0; 31 if(*a==' ') 32 { 33 if(t->n)return 0; 34 t->end=1; 35 return 1; 36 } 37 t->n++; 38 if(!t->next[*a-'0'])t->next[*a-'0']=inti(); 39 return insert(t->next[*a-'0'],a+1); 40 } 41 void del(trie* t) 42 { 43 int i; 44 for(i=0; i<10; ++i) 45 { 46 if(t->next[i] != NULL) 47 { 48 del(t->next[i]); 49 } 50 } 51 free(t); 52 } 53 int main() 54 { 55 int n,m; 56 int i,j; 57 cin>>n; 58 char a[11]; 59 for(i=0; i<n; i++) 60 { 61 trie *t; 62 t=inti(); 63 cin>>m; 64 int fla=0; 65 for(j=0; j<m; j++) 66 { 67 scanf("%s",a); 68 if(!fla&&!insert(t,a)) 69 fla=1; 70 } 71 if(!fla) 72 cout<<"YES"<<endl; 73 else cout<<"NO"<<endl; 74 del(t); 75 } 76 }