和书上写法不一样，输出的数是对的，但不确定能否通过测试。

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <queue>

using namespace std;

int main(){
    int n, m, t, animal;
    cin >> n;
    queue<int> dogs;
    queue<int> cats;
    queue<int> all;
    queue<int> ans;
    while(n--){
        cin >> m >> t;
        if(m == 1){
            if(t > 0){
                dogs.push(t);
            }else{
                cats.push(t);
            }
            all.push(t);
        }
        if(m == 2 && !all.empty()){
            if(t == 0 ){
                animal = all.front();    
                if(animal > 0 && !dogs.empty()) {
                    dogs.pop();
                    ans.push(animal);
                }
                else if(animal < 0 && !cats.empty()){
                    cats.pop();
                    ans.push(animal);
                }         
                all.pop();
            }else if(t == 1 && !dogs.empty()){
                ans.push(dogs.front());
                dogs.pop();
                all.pop();
            }else if(t == -1 && !cats.empty()){
                ans.push(cats.front());
                cats.pop();
                all.pop();
            }
        }
    }
    while(!ans.empty()){
        printf("%d ", ans.front());
        ans.pop();
    }

    return 0;
}

一些按照题目给的格式写的代码
https://blog.csdn.net/WYXHAHAHA123/article/details/97263876

题目下也有答案
https://www.nowcoder.com/questionTerminal/6235a76b1e404f748f7c820583125c50