Sum the Valid Numbers

Data typed by people is messy. You get a list of strings and must add up the ones that are whole numbers, ignoring the rest instead of crashing.

An entry counts if, after removing spaces at both ends, it is an optional + or - sign followed by one or more digits. Anything else (empty text, decimals such as "2.5", words) is skipped.

Implement sum_valid_numbers(values).

Input

values: The entries to read.

Output

Return the sum of the valid whole numbers (0 if there are none).

Restricciones

0 ≤ number of entries ≤ 1,000

Each entry has at most 20 characters; valid numbers fit in a 64-bit integer

Ejemplos

Entrada:
values = ["10", " 5 ", "abc", "-3"]

Salida esperada:
expected = 12

Entrada:
std::vector<std::string> values = {"10", " 5 ", "abc", "-3"};

Salida esperada:
long long expected = 12;

Entrada:
string[] values = new string[] {"10", " 5 ", "abc", "-3"};

Salida esperada:
long expected = 12;

Entrada:
values = ["2.5", "", "seven"]

Salida esperada:
expected = 0

Entrada:
std::vector<std::string> values = {"2.5", "", "seven"};

Salida esperada:
long long expected = 0;

Entrada:
string[] values = new string[] {"2.5", "", "seven"};

Salida esperada:
long expected = 0;

Referencias

Este reto está adaptado para CodeUtility. Sigue el enunciado y las restricciones indicadas arriba.

• Python docs, Errors and Exceptions