蓝桥杯水题专练

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>
using namespace std;
int main(){
    int N, q, a;
    scanf("%d", &N);
    queue<int>que;
    while(N--){
        scanf("%d", &q);
        switch(q){
            case 1:
                scanf("%d", &a);
                que.push(a);
                break;
            case 2:
                if(!que.empty()){
                    printf("%d\n", que.front());
                    que.pop();
                    break;
                }else{
                    printf("no\n");
                    exit(0);
                }
            case 3:
                printf("%d\n", que.size());
        }
    }
    return 0;
}