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
``````

Sample Output

``````NO
YES
``````

题解

``````91125426
911
``````

``````812345
8123456
``````

``````#include <bits/stdc++.h>
const int MAX_CHILDREN = 11;
struct node
{
bool end;
node *children[MAX_CHILDREN];
int count = 0;
~node() {
for (int i = MAX_CHILDREN - 1; i >= 0; i--)
{
if(children[i]) {
delete children[i];
}
}
}
node()
{
end = false;
for (int i = 0; i < MAX_CHILDREN; i++)
children[i] = NULL;
}
};
node *root;
bool yes = true;
/**
* 插入一个新的字符串
* @param str 字符串数组
* @param len 字符串长度
**/
void insert(char *str, int len)
{
node *location = root;
for (int i = 0; i < len; i++)
{
if (!yes)
return; // Thereisnoneed.
if (str[i] == 0 || str[i] == '\n')
continue;
int id = str[i] - '0';
if (location->children[id] == NULL)
{
location->children[id] = new node;
}
if (location->end)
{
yes = false;
return;
}
location = location->children[id];
location->count++;
}
location->end = true;
if (yes)
{
yes = location->count == 1;
}
}
char str[20];
int main()
{
int T;
scanf("%d", &T);
while (T--)
{
root = new node;
yes = true;
int n;
scanf("%d", &n);
while (n--)
{
scanf("%s", str);
int len = strlen(str);
insert(str, len);
}
printf("%s\n", yes ? "YES" : "NO");
delete root;
}
}
``````