解法：顺序表实现

#include<iostream>
#include<vector>
using namespace std;
struct SeqList {
	int* data;
	int front;
	int rear;
	int len;
};
void initList(SeqList* list,int size) {
	list->data = new int[size];
	list->len = size;
	list->front = 0;
	list->rear = 0;
	return;
}
bool empty(SeqList* list) {
	return list->front == list->rear;
}
bool isFull(SeqList* list) {
	return (list->rear + 1) % list->len == list->front;
}
void push(SeqList* list,int x) {
	if (!isFull(list)) {
		list->data[list->rear] = x;
		list->rear = (list->rear + 1) % list->len;
	}
	return;
}
int pop(SeqList* list) {
	int t = -1;
	if (!empty(list)) {
		t = list->data[list->front];
		list->front = (list->front + 1) % list->len;
	}
	return t;
}
int main() {
	SeqList l;
	int n, k;
	cin >> n >> k;
	initList(&l,n);
	string s;
	int a;
	while (k--) {
		cin >> s;
		if (s == "in") {
			cin >> a;
			push(&l, a);
		}
		else if (s == "out") {
			pop(&l);
		}
	}
	while (!empty(&l)) {
		cout << pop(&l) << " ";
	}
	return 0;
}

解法：链表实现

#include<iostream>
using namespace std;
class Myqueue {
public:
	struct Node {
		int val;
		Node* next;
		Node(int x) :val(x), next(NULL) {};
	};
	Myqueue() {
		dummyHead = new Node(0);
		tail = dummyHead;
		len = 1;
		capacity = 0;
	}
	void initQueue(int size) {
		capacity = size;
	}
	void push(int x) {
		if (len < capacity) {
			Node* newNode = new Node(x);
			tail->next = newNode;
			tail = tail->next;
			len++;
		}
	}
	int pop() {
		if (len > 0) {
			int t = dummyHead->next->val;
			Node* tmp = dummyHead->next;
			dummyHead->next = dummyHead->next->next;
			delete tmp;
			len--;
			return t;
		}
		return -1;
	}
	void printList() {
		Node* cur = dummyHead->next;
		while (cur != NULL) {
			cout << cur->val << " ";
			cur = cur->next;
		}
	}
private:
	Node* dummyHead;
	Node* tail;
	int len;
	int capacity;
};
int main() {
	Myqueue q;
	int n, k;
	cin >> n >> k;
	q.initQueue(n);
	string s;
	int a;
	while (k--) {
		cin >> s;
		if (s == "in") {
			cin >> a;
			q.push(a);
		}
		else if (s == "out") {
			q.pop();
		}
	}
	q.printList();
	return 0;
}

解法：STL实现

#include<iostream>
#include<queue>
using namespace std;

int main() {
	queue<int> q;
	int n, k;
	cin >> n >> k;
	string s;
	int a;
	while (k--) {
		cin >> s;
		if (s == "in") {
			cin >> a;
			if (q.size() + 1 < n) {
				q.push(a);
			}

		}
		else if (s == "out") {
			if (!q.empty()) {
				q.pop();
			}
		}
	}
	while (!q.empty()) {
		cout << q.front() << " ";
		q.pop();
	}
	return 0;
}