常用数据结构的插入、删除、读取

链表：
List list = new ArrayList<>();
    add		remove	
    //list.add(value);  list.add(index,value);

双向链表
LinkedList q = new LinkedList<>();
	q.addLast(n);	q.pollLast();	q.getLast()

栈
Deque stack = new ArrayDeque();
    push	pop		peek

双端队列
Deque d = new ArrayDeque<>();
	addFirst 	addLast 	pollFirst	pollLast  peekFirst  peekLast 

单向队列：LIFO 
Queue q = new LinkedList<>();
	push	pop   	peek

优先队列：
PriorityQueue pq = new PriorityQueue<>();
    offer 	poll	peek


哈希表：
Map map = new HashMap<>();
    put		remove  
    //remove(key);