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PHONELST - Phone List

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Phone List 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.


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.


For each test case, output “YES” if the list is consistent, or “NO” otherwise.




hide comments
raghav12345: 2015-11-14 10:51:02

stl rocks..
got two wa due to not using break;

angel_of_death: 2015-11-06 21:16:39

Wasted over 4 hours trying to debug my code when the problem was not declaring the arrays to be big enough. Absolutely f*ck my life lol.

Abhinandan Agarwal: 2015-10-25 09:39:02

NOTE:same phone numbers may appear more than once, they should indeed be treated as same. trie - 0.02s

Last edit: 2015-10-25 09:39:16
[Mayank Pratap]: 2015-10-20 10:39:21

Done earlier using STL :- 0.28
Now using trie :- 0.11

jarvis: 2015-09-27 17:00:54

STL :)

kartikay singh: 2015-08-31 17:29:50

STL do jobs easily :P

dwij28: 2015-08-29 20:02:28

I got an AC, but i am in a bit of confusion.
In the code which got AC, I had sorted the list and checked the (i-1)th element for being prefix to ith element where i belongs to [1, n]
But in a code which got WA, I sorted the the list and checked for ith element for being a prefix to (i+1)th element where i belongs to [0, n-1]. Cannot see what is wrong in this, as it does the same thing as the AC code .. :(

harshit sharma: 2015-07-25 12:18:06

simple :) no need of trie

vedaytas: 2015-06-25 21:05:17

nice first with trie.very basic trie

SangKuan: 2015-06-24 12:24:17

easy with trie tree,but i got 3 runtiome error,due to my node array is not enough,1 compilation error,because of it too big.

Added by:Andres Galvis
Time limit:0.177s-0.532s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel Pentium G860 3GHz)
Languages:All except: ERL JS NODEJS PERL 6
Resource:Nordic Collegiate Programming Contest 2007