Collections · interview question

Several threads add and read cached values by key at the same time. Which collection fits best?

Multiple choiceEasy

ConcurrentDictionary<TKey,TValue>Dictionary<TKey,TValue>List<KeyValuePair<TKey,TValue>>SortedList<TKey,TValue>

Answer and explanation

Correct answer

A. ConcurrentDictionary<TKey,TValue>

ConcurrentDictionary supports lock-free reads and fine-grained locking for writes, with atomic helpers like GetOrAdd and AddOrUpdate.

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