Problem
The singleton pattern makes sure a class has exactly one instance that everyone shares, a common choice for application settings.
Simulate one shared configuration that starts empty. Process the operations in order:
set <key> <value>: store the value for the key (replacing any old value).get <key>: read the key's current value, ormissingif it was never set.
Because every caller uses the same instance, a value set by one operation is visible to every later get.
Implement shared_configuration(operations).
Input
operations: Strings in the two forms above. Keys and values contain no spaces.
Output
Return the results of the get operations, in order.
Einschränkungen
1 ≤ number of operations ≤ 10,000
Keys and values have 1 to 20 characters
Beispiele
Eingabe:
operations = ["set theme dark", "get theme", "get language"]
Erwartete Ausgabe:
expected = ["dark", "missing"]Eingabe:
std::vector<std::string> operations = {"set theme dark", "get theme", "get language"};
Erwartete Ausgabe:
std::vector<std::string> expected = {"dark", "missing"};Eingabe:
string[] operations = new string[] {"set theme dark", "get theme", "get language"};
Erwartete Ausgabe:
string[] expected = new string[] {"dark", "missing"};Erläuterung
theme was set to dark; language was never set, so it is missing: ["dark", "missing"].
Eingabe:
operations = ["set lang en", "set lang vi", "get lang"]
Erwartete Ausgabe:
expected = ["vi"]Eingabe:
std::vector<std::string> operations = {"set lang en", "set lang vi", "get lang"};
Erwartete Ausgabe:
std::vector<std::string> expected = {"vi"};Eingabe:
string[] operations = new string[] {"set lang en", "set lang vi", "get lang"};
Erwartete Ausgabe:
string[] expected = new string[] {"vi"};Erläuterung
The second set replaces the first value in the same shared instance: ["vi"].
So gehst du vor
Versuch es zuerst allein und öffne dann einen Hinweis nach dem anderen.
Hinweis 1
All operations read and write the same single object.
Hinweis 2
A dictionary from key to value is enough to hold the settings.
Hinweis 3
A key that was never set must return the text missing.
Erwartete Komplexität
O(number of operations) time, O(number of keys) extra space
Referenzen
Diese Aufgabe wurde für CodeUtility angepasst. Beachte die oben genannten Vorgaben und Einschränkungen.