| Topic: | Phone List |
| Source Code: | phone.cpp |
|
In-Class Day: |
Thursday, Oct. 31 |
| Submission Deadline: | Sunday, Nov. 3, 11:59pm |
|
Techniques: |
Use of strings and system sort. |
The pre-lab requirement must be completed and submitted individually.
The remainder of the lab activity can be completed working in pairs. One person should submit the result, making sure that both partners' names are clearly identified in that submission.
Please make sure you adhere to the policies on academic integrity in this regard.
Read the complete problem description and then determine what the expected output should be if given the following input:
| Prelab input: | Prelab output: |
|
3 3 9777039 9772444 3149777039 3 012 12 210 4 3 4 1234 4321 |
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:
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 hte list is consistent, or "NO" otherwise.
| Example input: | Example output: |
| 2 3 911 97625999 91125426 5 113 12340 123440 12345 98346 |
NO YES |
Although this problem is about "numbers", you should store all of these as strings.
Then, the key to efficiency for this problem is to first sort the list of strings, and then you can determine consistency by checking whether any entry is a prefix of the one immediately following it.
Useful documentation:
Sorting can be done with sort function from the <algorithm> library, for arrays and vectors, or the sort method of the list class.
Syntax for sorting array A of length n is: sort(A, A+n).
Syntax for sorting vector V: sort(V.begin(), V.end()).
Syntax for sorting list L: L.sort().