LRU算法C++实现

使用 unordered_map 和 双向链表简单实现的LRU算法，C++实现：第一种是普通写法，第二种是模板类写法。

#include <iostream>
#include <unordered_map>

using namespace std;

struct CacheNode {
	int key;
	int value;
	CacheNode *pre, *next;
	CacheNode(int k, int v) : key(k), value(v), pre(nullptr), next(nullptr) {}
};

class LRUCache {
private:
	int size;
	CacheNode *head, *tail;
	unordered_map<int, CacheNode*> mp;

public:
	LRUCache(int capacity): size(capacity), head(nullptr), tail(nullptr) {}

	void remove(CacheNode *node) {
		if (nullptr != node->pre) {
			node->pre->next = node->next;
		}
		else {
			head = node->next;
		}
		if (nullptr != node->next) {
			node->next->pre = node->pre;
		}
		else {
			tail = node->pre;
		}
	}

	void setHead(CacheNode *node) {
		node->next = head;
		node->pre = nullptr;
		if (nullptr != head) {
			head->pre = node;
		}
		head = n