Problema
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.
Restricciones
1 ≤ number of operations ≤ 10,000
Keys and values have 1 to 20 characters
Ejemplos
Entrada:
operations = ["set theme dark", "get theme", "get language"]
Salida esperada:
expected = ["dark", "missing"]Entrada:
std::vector<std::string> operations = {"set theme dark", "get theme", "get language"};
Salida esperada:
std::vector<std::string> expected = {"dark", "missing"};Entrada:
string[] operations = new string[] {"set theme dark", "get theme", "get language"};
Salida esperada:
string[] expected = new string[] {"dark", "missing"};Explicación
theme was set to dark; language was never set, so it is missing: ["dark", "missing"].
Entrada:
operations = ["set lang en", "set lang vi", "get lang"]
Salida esperada:
expected = ["vi"]Entrada:
std::vector<std::string> operations = {"set lang en", "set lang vi", "get lang"};
Salida esperada:
std::vector<std::string> expected = {"vi"};Entrada:
string[] operations = new string[] {"set lang en", "set lang vi", "get lang"};
Salida esperada:
string[] expected = new string[] {"vi"};Explicación
The second set replaces the first value in the same shared instance: ["vi"].
Cómo abordarlo
Inténtalo primero por tu cuenta y luego abre las pistas una a una.
Pista 1
All operations read and write the same single object.
Pista 2
A dictionary from key to value is enough to hold the settings.
Pista 3
A key that was never set must return the text missing.
Complejidad esperada
O(number of operations) time, O(number of keys) extra space
Referencias
Este reto está adaptado para CodeUtility. Sigue el enunciado y las restricciones indicadas arriba.