Problema
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).
Restrições
0 ≤ number of entries ≤ 1,000
Each entry has at most 20 characters; valid numbers fit in a 64-bit integer
Exemplos
Entrada:
values = ["10", " 5 ", "abc", "-3"]
Saída esperada:
expected = 12Entrada:
std::vector<std::string> values = {"10", " 5 ", "abc", "-3"};
Saída esperada:
long long expected = 12;Entrada:
string[] values = new string[] {"10", " 5 ", "abc", "-3"};
Saída esperada:
long expected = 12;Explicação
"10", " 5 " (spaces are trimmed) and "-3" are whole numbers; "abc" is skipped. 10 + 5 - 3 = 12.
Entrada:
values = ["2.5", "", "seven"]
Saída esperada:
expected = 0Entrada:
std::vector<std::string> values = {"2.5", "", "seven"};
Saída esperada:
long long expected = 0;Entrada:
string[] values = new string[] {"2.5", "", "seven"};
Saída esperada:
long expected = 0;Explicação
None of the entries is a whole number, so the sum is 0.
Como abordar
Tente sozinho primeiro e depois abra uma dica de cada vez.
Dica 1
Strip the spaces first, then decide whether what is left is a valid whole number.
Dica 2
Converting inside try/except (or checking the characters) lets you skip bad entries without stopping.
Dica 3
Remember that a lone sign such as "+" is not a number.
Complexidade esperada
O(total length) time, O(1) extra space
Referências
Este desafio foi adaptado para o CodeUtility. Siga o enunciado e as restrições acima.