add 146.LRUCache Solution in CPP and GO

Author: KongJHong

solution/0146.Lru Cache/Solution.cpp

@@ -0,0 +1,57 @@
+class LRUCache {
+	private:
+		int _cap;
+		// 双链表：装着 (key, value) 元组
+		list<pair<int, int>> cache;
+		// 哈希表：key 映射到 (key, value) 在 cache 中的位置
+		unordered_map<int, list<pair<int, int>>::iterator> umap;
+	public:
+	   LRUCache(int capacity) {
+			_cap = capacity;
+			
+		}
+		
+		int get(int key) {
+			auto iter = umap.find(key);
+			if(iter == umap.end())return -1;
+			
+			pair<int,int> kv = *umap[key];
+			cache.erase(umap[key]);//改
+			cache.push_front(kv);
+			umap[key] = cache.begin();
+			
+			return kv.second;
+		}
+		
+		void put(int key, int value) {
+			auto iter = umap.find(key);
+			if(iter != umap.end()){ //存在于缓存
+				
+				cache.erase(umap[key]);
+				cache.push_front(make_pair(key,value));
+				umap[key] = cache.begin(); 
+				
+				return;
+			}
+			
+			
+			//不在缓存中
+			if(cache.size() == _cap) //满了
+			{
+				
+				auto iter = cache.back();
+				umap.erase(iter.first);
+				cache.pop_back();
+				
+				cache.push_front(make_pair(key,value));
+				umap[key] = cache.begin();
+				
+			}
+			else                    //没满
+			{
+				cache.push_front(make_pair(key,value));
+				umap[key] = cache.begin();
+				
+			}
+		}
+	};

solution/0146.Lru Cache/Solution.go

@@ -0,0 +1,105 @@
+type list struct{   //双向链表,用于保存key:value
+    prev,next *list
+    key,val int
+}
+
+type LRUCache struct {
+    _len,_cap int
+    front,back *list    //头尾指针
+    umap map[int]*list  //hash表
+}
+  
+
+func Constructor(capacity int) LRUCache {
+    return LRUCache{
+        _len : 0,
+        _cap : capacity,
+        front: nil,
+        back : nil,
+        umap : make(map[int]*list,capacity),
+    }
+}
+
+
+func (this *LRUCache) Get(key int) int {
+    if node,ok := this.umap[key];ok{  //存在
+        
+        this.push_front(node)
+        return node.val
+    }
+    
+    return -1
+}
+
+
+func (this *LRUCache) Put(key int, value int)  {
+    if node,ok := this.umap[key];ok{ 
+        node.val = value
+        this.push_front(node)
+        return 
+    }
+    
+    //找不到
+    if this._len == this._cap{
+        delete(this.umap,this.back.key)
+        this.pop_back()
+    }else{
+        this._len++
+    }
+    
+    node := &list{
+        prev:nil,
+        next:nil,
+        key:key,
+        val:value,
+    }
+    
+    this.umap[key] = node
+    this.insert_front(node)  
+}
+
+
+func (this *LRUCache) push_front(node *list){
+    switch node{    //先删除，再插入
+    case this.front:
+        return
+    case this.back:
+        this.pop_back()
+    default:
+        node.prev.next = node.next
+        node.next.prev = node.prev
+    }
+    
+    this.insert_front(node)
+}
+
+func (this *LRUCache) pop_back(){
+    if this.back.prev != nil{ //链表长度大于1
+        this.back.prev.next = nil
+    }else{                      //链表长度小于等于1
+        this.front = nil
+    }
+    
+    this.back = this.back.prev
+}
+
+
+func (this *LRUCache)insert_front(node *list){
+    if this.back == nil{
+        //空表
+        this.back = node
+    }else{ //头插法
+        node.next = this.front
+        this.front.prev = node
+    }
+    
+    this.front = node
+}
+
+
+/**
+ * Your LRUCache object will be instantiated and called as such:
+ * obj := Constructor(capacity);
+ * param_1 := obj.Get(key);
+ * obj.Put(key,value);
+ */