本质理解上数据结构stack、queue 在Java中很别扭？那就打

[stack ==> ArrayDeque 或 LinkedList]
Swap Stack Mapping Last尾缀系, 
peek() == peekLast()
pop()  == pollLast() 
push() == addLast()

[queue ==> ArrayDeque 或 LinkedList]
Swap queue Mapping , 
peek() == peek() 
poll() == poll() 
add()  == add()