Problème
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).
Contraintes
0 ≤ number of entries ≤ 1,000
Each entry has at most 20 characters; valid numbers fit in a 64-bit integer
Exemples
Entrée :
values = ["10", " 5 ", "abc", "-3"]
Sortie attendue :
expected = 12
Entrée :
std::vector<std::string> values = {"10", " 5 ", "abc", "-3"};
Sortie attendue :
long long expected = 12;
Entrée :
string[] values = new string[] {"10", " 5 ", "abc", "-3"};
Sortie attendue :
long expected = 12;
Explication
"10", " 5 " (spaces are trimmed) and "-3" are whole numbers; "abc" is skipped. 10 + 5 - 3 = 12.
Entrée :
values = ["2.5", "", "seven"]
Sortie attendue :
expected = 0
Entrée :
std::vector<std::string> values = {"2.5", "", "seven"};
Sortie attendue :
long long expected = 0;
Entrée :
string[] values = new string[] {"2.5", "", "seven"};
Sortie attendue :
long expected = 0;
Explication
None of the entries is a whole number, so the sum is 0.
Comment l'aborder
Essayez d'abord seul, puis ouvrez les indices un par un.
Indice 1
Strip the spaces first, then decide whether what is left is a valid whole number.
Indice 2
Converting inside try/except (or checking the characters) lets you skip bad entries without stopping.
Indice 3
Remember that a lone sign such as "+" is not a number.
Complexité attendue
O(total length) time, O(1) extra space
Références
Ce défi a été adapté pour CodeUtility. Suivez l'énoncé et les contraintes ci-dessus.