剑指 Offer 09. 用两个栈实现队列

[Tcdian]

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 )

Example 1

输入：
["CQueue","appendTail","deleteHead","deleteHead"]
[[],[3],[],[]]
输出：[null,null,3,-1]

Example 2

输入：
["CQueue","deleteHead","appendTail","appendTail","deleteHead","deleteHead"]
[[],[],[5],[2],[],[]]
输出：[null,-1,null,null,5,2]

Note

• 1 <= values <= 10000
• 最多会对 appendTail、deleteHead 进行 10000 次调用

[Tcdian]

Solution

• TypeScript Solution

class CQueue {
    private data: number[];
    private aid: number[];
    constructor() {
        this.data = [];
        this.aid = [];
    }

    appendTail(value: number): void {
        this.data.push(value);
    }

    deleteHead(): number {
        if (this.data.length === 0) {
            return -1;
        }
        while (this.data.length > 1) {
            this.aid.push(this.data.pop() as number);
        }
        const deletedEl = this.data.pop() as number;
        while (this.aid.length !== 0) {
            this.data.push(this.aid.pop() as number);
        }
        return deletedEl;
    }
}

/**
 * Your CQueue object will be instantiated and called as such:
 * var obj = new CQueue()
 * obj.appendTail(value)
 * var param_2 = obj.deleteHead()
 */