146.LRUCache.go

package linkedList

typeLRUCachestruct {
capacityint
hashmap[int]*DListNode
Head*DListNode
Tail*DListNode
}

funcConstructor(capacityint) *LRUCache {
head:=&DListNode{Key: -1, Val: -1}
tail:=&DListNode{Key: -1, Val: -1}
head.Next=tail
tail.Prev=head

cache:=&LRUCache{
capacity: capacity,
hash: make(map[int]*DListNode, capacity),
Head: head,
Tail: tail,
 }
returncache
}

func (lru*LRUCache) insert(node*DListNode) {
t:=lru.Tail
node.Prev=t.Prev
t.Prev.Next=node
node.Next=t
t.Prev=node
}

func (lru*LRUCache) remove(node*DListNode) {
node.Prev.Next=node.Next
node.Next.Prev=node.Prev
}

func (lru*LRUCache) Len() int {
returnlen(lru.hash)
}

func (lru*LRUCache) Cap() int {
returnlru.capacity
}

func (lru*LRUCache) Get(keyint) int {
ifv, ok:=lru.hash[key]; ok {
lru.remove(v)
lru.insert(v)
returnv.Val
 }
return-1
}

func (lru*LRUCache) Put(key, valint) {
ifv, ok:=lru.hash[key]; ok {
lru.remove(v)
lru.insert(v)
v.Val=val
 } else {
iflru.Len() ==lru.Cap() {
h:=lru.Head.Next
lru.remove(h)
// Import! update lru.hash
delete(lru.hash, h.Key)
 }
node:=&DListNode{
Key: key,
Val: val,
 }
lru.hash[key] =node
lru.insert(node)
 }
}