Description:
Design a data structure that follows the constraints of a Least Recently Used (LRU) cache.
Implement the LRUCache class:
LRUCache(int capacity) Initialize the LRU cache with positive size capacity.
int get(int key) Return the value of the key if the key exists, otherwise return -1.
void put(int key, int value) Update the value of the key if the key exists. Otherwise, add the key-value pair to the cache. If the number of keys exceeds the capacity from this operation, evict the least recently used key.
Solution:
class LRUCache {
constructor(capacity) {
this.cache = new Map();
this.capacity = capacity;
}
get(key) {
if (!this.cache.has(key)) return -1;
const v = this.cache.get(key);
this.cache.delete(key);
this.cache.set(key, v);
return this.cache.get(key);
};
put(key, value) {
if (this.cache.has(key)) {
this.cache.delete(key);
}
this.cache.set(key, value);
if (this.cache.size > this.capacity) {
this.cache.delete(this.cache.keys().next().value); // keys().next().value returns first item's key
}
};
}
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