剑指 Offer 09. 用两个栈实现队列
用两个栈实现一个队列。队列的声明如下，请实现它的两个函数 appendTail 和 deleteHead ，分别完成在队列尾部插入整数和在队列头部删除整数的功能。(若队列中没有元素，deleteHead 操作返回 -1 )
示例 1：
输入： ["CQueue","appendTail","deleteHead","deleteHead"] [[],[3],[],[]] 输出：[null,null,3,-1]
示例 2：
输入： ["CQueue","deleteHead","appendTail","appendTail","deleteHead","deleteHead"] [[],[],[5],[2],[],[]] 输出：[null,-1,null,null,5,2]
提示：
1 <= values <= 10000最多会对 appendTail、deleteHead 进行 10000 次调用原站题解
golang 解法, 执行用时: 160 ms, 内存消耗: 8 MB, 提交时间: 2022-08-25 15:28:42
type CQueue struct {
inStack, outStack []int
}
func Constructor() CQueue {
return CQueue{}
}
func (this *CQueue) AppendTail(value int) {
this.inStack = append(this.inStack, value)
}
func (this *CQueue) DeleteHead() int {
if len(this.outStack) == 0 {
if len(this.inStack) == 0 {
return -1
}
this.in2out()
}
value := this.outStack[len(this.outStack)-1]
this.outStack = this.outStack[:len(this.outStack)-1]
return value
}
func (this *CQueue) in2out() {
for len(this.inStack) > 0 {
this.outStack = append(this.outStack, this.inStack[len(this.inStack)-1])
this.inStack = this.inStack[:len(this.inStack)-1]
}
}
/**
* Your CQueue object will be instantiated and called as such:
* obj := Constructor();
* obj.AppendTail(value);
* param_2 := obj.DeleteHead();
*/
python3 解法, 执行用时: 372 ms, 内存消耗: 19.2 MB, 提交时间: 2022-08-25 15:27:29
class CQueue:
def __init__(self):
self.q = []
def appendTail(self, value: int) -> None:
self.q.append(value)
def deleteHead(self) -> int:
if len(self.q) == 0: return -1
t = self.q[0]
self.q = self.q[1:]
return t
# Your CQueue object will be instantiated and called as such:
# obj = CQueue()
# obj.appendTail(value)
# param_2 = obj.deleteHead()
golang 解法, 执行用时: 292 ms, 内存消耗: 8.6 MB, 提交时间: 2021-06-10 20:53:28
type CQueue struct {
q []int
}
func Constructor() CQueue {
return CQueue{
q: []int{},
}
}
func (this *CQueue) AppendTail(value int) {
this.q = append(this.q, value)
}
func (this *CQueue) DeleteHead() int {
if len(this.q) == 0 {
return -1
}
t := this.q[0]
this.q = this.q[1:]
return t
}
/**
* Your CQueue object will be instantiated and called as such:
* obj := Constructor();
* obj.AppendTail(value);
* param_2 := obj.DeleteHead();
*/