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| 1 | +/* |
| 2 | + |
| 3 | +Write a class that allows getting and setting key-value pairs, however a time until expiration is associated with each key. |
| 4 | + |
| 5 | +The class has three public methods: |
| 6 | + |
| 7 | +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. |
| 8 | + |
| 9 | +get(key): if an un-expired key exists, it should return the associated value. Otherwise it should return -1. |
| 10 | + |
| 11 | +count(): returns the count of un-expired keys. |
| 12 | + |
| 13 | + |
| 14 | + |
| 15 | +Example 1: |
| 16 | + |
| 17 | +Input: |
| 18 | +actions = ["TimeLimitedCache", "set", "get", "count", "get"] |
| 19 | +values = [[], [1, 42, 100], [1], [], [1]] |
| 20 | +timeDelays = [0, 0, 50, 50, 150] |
| 21 | +Output: [null, false, 42, 1, -1] |
| 22 | +Explanation: |
| 23 | +At t=0, the cache is constructed. |
| 24 | +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. |
| 25 | +At t=50, key=1 is requested and the value of 42 is returned. |
| 26 | +At t=50, count() is called and there is one active key in the cache. |
| 27 | +At t=100, key=1 expires. |
| 28 | +At t=150, get(1) is called but -1 is returned because the cache is empty. |
| 29 | +Example 2: |
| 30 | + |
| 31 | +Input: |
| 32 | +actions = ["TimeLimitedCache", "set", "set", "get", "get", "get", "count"] |
| 33 | +values = [[], [1, 42, 50], [1, 50, 100], [1], [1], [1], []] |
| 34 | +timeDelays = [0, 0, 40, 50, 120, 200, 250] |
| 35 | +Output: [null, false, true, 50, 50, -1, 0] |
| 36 | +Explanation: |
| 37 | +At t=0, the cache is constructed. |
| 38 | +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. |
| 39 | +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. |
| 40 | +At t=50, get(1) is called which returned 50. |
| 41 | +At t=120, get(1) is called which returned 50. |
| 42 | +At t=140, key=1 expires. |
| 43 | +At t=200, get(1) is called but the cache is empty so -1 is returned. |
| 44 | +At t=250, count() returns 0 because the cache is empty. |
| 45 | + |
| 46 | + |
| 47 | +Constraints: |
| 48 | + |
| 49 | +0 <= key, value <= 109 |
| 50 | +0 <= duration <= 1000 |
| 51 | +1 <= actions.length <= 100 |
| 52 | +actions.length === values.length |
| 53 | +actions.length === timeDelays.length |
| 54 | +0 <= timeDelays[i] <= 1450 |
| 55 | +actions[i] is one of "TimeLimitedCache", "set", "get" and "count" |
| 56 | +First action is always "TimeLimitedCache" and must be executed immediately, with a 0-millisecond delay |
| 57 | + |
| 58 | + |
| 59 | + |
| 60 | + |
| 61 | + |
| 62 | + |
| 63 | +*/ |
| 64 | + |
| 65 | + |
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