Why caching reduces latency in HLD - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to show where cached data is stored.

HLD

cache = [1]()

Drag options to blanks, or click blank then click option'

Adatabase

Bnetwork

Cdisk

Din-memory

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing disk or database instead of in-memory storage.

Caching stores data in in-memory to allow faster access than disk or network.

2fill in blank

medium

Complete the code to check if data is in cache before fetching from source.

HLD

if key [1] cache:
    return cache[key]

Drag options to blanks, or click blank then click option'

Aequals

Bin

Cnot in

Dcontains

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'not in' which checks absence instead of presence.

We check if the key is in the cache to use cached data and reduce latency.

3fill in blank

hard

Fix the error in the code that updates the cache after fetching data.

HLD

data = fetch_from_source(key)
cache[[1]] = data

Drag options to blanks, or click blank then click option'

Akey

Bvalue

Cdata

Dsource

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'value' or 'data' as the cache key instead of 'key'.

The cache key must be the key used to fetch data, not the value or data itself.

4fill in blank

hard

Fill both blanks to complete the code that returns cached data or fetches and caches it.

HLD

if [1] in cache:
    return cache[[2]]

Drag options to blanks, or click blank then click option'

Akey

Bdata

Cvalue

Dsource

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variables for checking and accessing cache.

Both blanks must be the key to check and retrieve the cached data correctly.

5fill in blank

hard

Fill all three blanks to complete the caching logic with fetch and store.

HLD

if [1] not in cache:
    [2] = fetch_from_source([3])
    cache[key] = data

Drag options to blanks, or click blank then click option'

Akey

Bdata

Dsource

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing variable names or using undefined variables.

Check if key is missing, fetch data into data, and use key to store it in cache.