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).
Vincoli
0 ≤ number of entries ≤ 1,000
Each entry has at most 20 characters; valid numbers fit in a 64-bit integer
Esempi
Input:
values = ["10", " 5 ", "abc", "-3"]
Output atteso:
expected = 12Input:
std::vector<std::string> values = {"10", " 5 ", "abc", "-3"};
Output atteso:
long long expected = 12;Input:
string[] values = new string[] {"10", " 5 ", "abc", "-3"};
Output atteso:
long expected = 12;Spiegazione
"10", " 5 " (spaces are trimmed) and "-3" are whole numbers; "abc" is skipped. 10 + 5 - 3 = 12.
Input:
values = ["2.5", "", "seven"]
Output atteso:
expected = 0Input:
std::vector<std::string> values = {"2.5", "", "seven"};
Output atteso:
long long expected = 0;Input:
string[] values = new string[] {"2.5", "", "seven"};
Output atteso:
long expected = 0;Spiegazione
None of the entries is a whole number, so the sum is 0.
Come affrontarlo
Prova prima da solo, poi apri un suggerimento alla volta.
Suggerimento 1
Strip the spaces first, then decide whether what is left is a valid whole number.
Suggerimento 2
Converting inside try/except (or checking the characters) lets you skip bad entries without stopping.
Suggerimento 3
Remember that a lone sign such as "+" is not a number.
Complessità attesa
O(total length) time, O(1) extra space
Riferimenti
Questa sfida è adattata per CodeUtility. Segui la traccia e i vincoli sopra.