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LRUCache.cpp
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LRUCache.cpp
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/*
*LRU Cache
*Author: shuaijiang
*Email: zhaoshuaijiang8@gmail.com
*/
#include<iostream>
#include<stack>
#include<stdlib.h>
using namespace std;
class LRUCache{
public:
LRUCache(int capacity) {
this->capacity = capacity;
}
int get(int key) {
if(cacheMap.find(key) == cacheMap.end())
return -1;
cacheList.splice(cacheList.begin(), cacheList, cacheMap[key]);
cacheMap[key] = cacheList.begin();
return cacheMap[key]->value;
}
void set(int key, int value) {
if(cacheMap.find(key) == cacheMap.end()){
if(capacity == cacheList.size()){
cacheMap.erase(cacheList.back().key);
cacheList.pop_back();
}
CacheNode node(key,value);
cacheList.push_front(node);
cacheMap[key] = cacheList.begin();
}
else{
cacheList.splice(cacheList.begin(), cacheList, cacheMap[key]);
cacheMap[key] = cacheList.begin();
cacheMap[key]->value = value;
}
}
private:
struct CacheNode{
int key;
int value;
CacheNode(int k, int v):key(k), value(v){}
};
int capacity;
list<CacheNode> cacheList;
map<int, list<CacheNode>::iterator> cacheMap;
};