Count Top Area Codes | Dataford Interview Questions

From a list of phone numbers, remove the ones with the wrong format and count the 3 highest area codes.

Treat a phone number as valid only when it matches XXX-XXX-XXXX, where every X is a digit. Implement count_area_codes(phone_numbers), which accepts an array of strings and returns up to three [area_code, count] pairs. Sort by descending count, then ascending numeric area code when counts tie.

Constraints

0 <= phone_numbers.length <= 1000
Each phone number contains printable characters and has length at most 20
A valid phone number has exactly the format XXX-XXX-XXXX
Return at most three area codes
For equal counts, sort area codes in ascending numeric order

Function Signature

def count_area_codes(phone_numbers):

Your question is Count Top Area Codes. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

From a list of phone numbers, remove the ones with the wrong format and count the 3 highest area codes.

Constraints

0 <= phone_numbers.length <= 1000
Each phone number contains printable characters and has length at most 20
A valid phone number has exactly the format XXX-XXX-XXXX
Return at most three area codes
For equal counts, sort area codes in ascending numeric order

Function Signature

def count_area_codes(phone_numbers):

Your question is Count Top Area Codes. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.