2622. Cache With Time Limit
Write a class that allows getting and setting key-value pairs, however a time until expiration is associated with each key.
The class has three public methods:
set(key, value, duration): accepts an integer key, an integer value, and a duration in
milliseconds.
Once the duration has elapsed, the key should be inaccessible. The method should return true if
the
same un-expired key already exists and false otherwise. Both the value and duration should be
overwritten if the key already exists.
get(key): if an un-expired key exists, it should return the associated value. Otherwise it should
return -1.
count(): returns the count of un-expired keys.
Example 1:
Input: ["TimeLimitedCache", "set", "get", "count", "get"] [[], [1, 42, 100], [1], [], [1]] [0, 0, 50, 50, 150] Output: [null, false, 42, 1, -1] Explanation: At t=0, the cache is constructed. At t=0, a key-value pair (1: 42) is added with a time limit of 100ms. The value doesn't exist so false is returned. At t=50, key=1 is requested and the value of 42 is returned. At t=50, count() is called and there is one active key in the cache. At t=100, key=1 expires. At t=150, get(1) is called but -1 is returned because the cache is empty.
Example 2:
Input: ["TimeLimitedCache", "set", "set", "get", "get", "get", "count"] [[], [1, 42, 50], [1, 50, 100], [1], [1], [1], []] [0, 0, 40, 50, 120, 200, 250] Output: [null, false, true, 50, 50, -1] Explanation: At t=0, the cache is constructed. At t=0, a key-value pair (1: 42) is added with a time limit of 50ms. The value doesn't exist so false is returned. At t=40, a key-value pair (1: 50) is added with a time limit of 100ms. A non-expired value already existed so true is returned and the old value was overwritten. At t=50, get(1) is called which returned 50. At t=120, get(1) is called which returned 50. At t=140, key=1 expires. At t=200, get(1) is called but the cache is empty so -1 is returned. At t=250, count() returns 0 because the cache is empty.
0 <= key <= 1090 <= value <= 1090 <= duration <= 1000total method calls will not exceed 100