題解：

字典樹判斷該字串是不是串集裡某個字串字首

程式碼

#include <cstdio>
#include <queue>
#include <cstring>
#include <iostream>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <map>
#include <string>
#include <set>
#include <ctime>
#include <cmath>
 

#include <cctype>
using namespace std;
#define maxn 100010
#define LL long long
int cas=1,T;
struct Tree
{
   int Next[maxn][11];
   int word[maxn];
   int L,root;

   void init()
   {
       L = 0;
       root = newnode();
   }
   int newnode()
   {
       for (int i = 0;i<11;i++)
           Next[L][i] = -1
 
;
       word[L++] = 0;
       return L-1;
   }

   void insert(char *s)
   {
      int l = strlen(s);
      int u = root;
      for (int i = 0;i<l;i++)
      {
         int c = s[i]-'0';
         if (Next[u][c] == -1)
             Next[u][c] = newnode();
         u = Next[u][c];
         word[u]++;
      }
   }

   int
 
 judgeprefix(char *s)
   {
       int l = strlen(s);
       int u = root;
       for (int i = 0;i<l;i++)
       {
           int c = s[i] - '0';
           u = Next[u][c];
           if (word[u] == 1)           //不是字首
               return 1;           
       }
       return 0;
   }

};
char a[10001][10];
int main()
{
    scanf("%d",&T);
    while (T--)
    {
        int n;
        Tree tree;
        tree.init();
        scanf("%d",&n);
        for (int i = 0;i<n;i++)
        {
           scanf("%s",a[i]);
           tree.insert(a[i]);
        }
        int flag = 1;
        for (int i = 0;i<n;i++)
        {
            flag = tree.judgeprefix(a[i]);
            if (flag == 0)
            {
                printf("NO\n");
                break;
            }
        }
        if (flag) printf("YES\n");
    }
    return 0;
}

題目

Phone List

Time Limit:1000MS Memory Limit:65536KB 64bit IO Format:%I64d & %I64u

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:

Emergency 911
Alice 97 625 999
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

Sample Output

NO
YES