Problem
C# records compare by value: two records are equal when all their fields are equal, even if they are different objects. That makes removing duplicates easy.
Each record is written name,city. Trim spaces around both fields; after trimming, two records are equal when both fields match exactly (case matters).
Implement unique_records(records).
Input
records: The records, in order.
Output
Return the distinct records in the order they first appear, written name,city with the trimmed fields.
Constraints
0 ≤ number of records ≤ 100,000
Each field has 1 to 30 characters and no commas
Examples
Input:
records = ["Ada,London", "Lin, Hanoi", "Ada , London"]
Expected output:
expected = ["Ada,London", "Lin,Hanoi"]Input:
std::vector<std::string> records = {"Ada,London", "Lin, Hanoi", "Ada , London"};
Expected output:
std::vector<std::string> expected = {"Ada,London", "Lin,Hanoi"};Input:
string[] records = new string[] {"Ada,London", "Lin, Hanoi", "Ada , London"};
Expected output:
string[] expected = new string[] {"Ada,London", "Lin,Hanoi"};Explanation
After trimming, the third record equals the first, so it is dropped: ["Ada,London", "Lin,Hanoi"].
Input:
records = ["ada,Paris", "Ada,Paris"]
Expected output:
expected = ["ada,Paris", "Ada,Paris"]Input:
std::vector<std::string> records = {"ada,Paris", "Ada,Paris"};
Expected output:
std::vector<std::string> expected = {"ada,Paris", "Ada,Paris"};Input:
string[] records = new string[] {"ada,Paris", "Ada,Paris"};
Expected output:
string[] expected = new string[] {"ada,Paris", "Ada,Paris"};Explanation
Case matters, so these two records are different: ["ada,Paris", "Ada,Paris"].
How to approach it
Try on your own first, then open one hint at a time.
Hint 1
Trim both fields before comparing records.
Hint 2
A set of (name, city) pairs remembers which records you have seen.
Hint 3
Output each new record the first time it appears, in input order.
Expected complexity
O(total length) time, O(number of records) extra space
References
This challenge is adapted for CodeUtility. Follow the statement and constraints above.