LeetCode refers to Offer 09. Implement queue with two stacks

The title

Implement a queue with two stacks. Implement appendTail and deleteHead to insert an integer at the end of the queue and delete an integer at the head of the queue. (If there are no elements in the queue, the deleteHead operation returns -1)

Example 1: Enter: ["CQueue"."appendTail"."deleteHead"."deleteHead"] [[],[3],[] output: [NULL, NULL,3,-1] Example 2: Input: ["CQueue"."deleteHead"."appendTail"."appendTail"."deleteHead"."deleteHead"[[]], [], [5], [2], [], []] output: [null, 1, null, null, 5, 2]Copy the code

Tip:

1 <= values <= 10000 Calls to appendTail and deleteHead are performed at most 10000 times

Their thinking

class CQueue:
    def __init__(self):
        self.queueListOut = []
        self.queueListTemp = []
    def appendTail(self, value: int) -> None:
        self.queueListTemp.append(value)

    def deleteHead(self) -> int:
        if len(self.queueListOut) <= 0 and len(self.queueListTemp)<= 0: return- 1iflen(self.queueListOut) ! = 0:return self.queueListOut.pop()
        whilelen(self.queueListTemp) ! = 0: self.queueListOut.append(self.queueListTemp.pop())return self.queueListOut.pop()
Copy the code