Problem
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).
Einschränkungen
0 ≤ number of entries ≤ 1,000
Each entry has at most 20 characters; valid numbers fit in a 64-bit integer
Beispiele
Eingabe:
values = ["10", " 5 ", "abc", "-3"]
Erwartete Ausgabe:
expected = 12
Eingabe:
std::vector<std::string> values = {"10", " 5 ", "abc", "-3"};
Erwartete Ausgabe:
long long expected = 12;
Eingabe:
string[] values = new string[] {"10", " 5 ", "abc", "-3"};
Erwartete Ausgabe:
long expected = 12;
Erläuterung
"10", " 5 " (spaces are trimmed) and "-3" are whole numbers; "abc" is skipped. 10 + 5 - 3 = 12.
Eingabe:
values = ["2.5", "", "seven"]
Erwartete Ausgabe:
expected = 0
Eingabe:
std::vector<std::string> values = {"2.5", "", "seven"};
Erwartete Ausgabe:
long long expected = 0;
Eingabe:
string[] values = new string[] {"2.5", "", "seven"};
Erwartete Ausgabe:
long expected = 0;
Erläuterung
None of the entries is a whole number, so the sum is 0.
So gehst du vor
Versuch es zuerst allein und öffne dann einen Hinweis nach dem anderen.
Hinweis 1
Strip the spaces first, then decide whether what is left is a valid whole number.
Hinweis 2
Converting inside try/except (or checking the characters) lets you skip bad entries without stopping.
Hinweis 3
Remember that a lone sign such as "+" is not a number.
Erwartete Komplexität
O(total length) time, O(1) extra space
Referenzen
Diese Aufgabe wurde für CodeUtility angepasst. Beachte die oben genannten Vorgaben und Einschränkungen.