33 lines
715 B
Markdown
33 lines
715 B
Markdown
# LRU cache
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The standard implemenation of LRU cache (hash table + doubly-linked list).
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All operations are in time complexity of O(1).
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This implementation is *not* thread-safe.
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## Usage
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```
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# create a new LRU cache with initial capacity of 1 items
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let cache = newLRUCache[int, string](1)
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cache[1] = "a"
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cache[2] = "b"
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# key 1 is not in cache, because key 1 is eldest and capacity is only 1
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assert: 1 notin cache
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assert: 2 in cache
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# increase capacity and add key 1
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cache.capacity = 2
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cache[1] = "a"
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assert: 1 in cache
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assert: 2 in cache
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# update recentness of key 2 and add key 3, then key 1 will be discarded.
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echo cache[2]
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cache[3] = "c"
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assert: 1 notin cache
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assert: 2 in cache
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assert: 3 in cache
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```
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