题解 | #[USACO 2009 Ope S]Cow Line#

这是到典型的双端队列题，运用模拟思想将牛队列看作是双端队列即可。

	int times;
    cin>>times;
    deque<int> cows;
    int ncow=1;
    char order;
    char side;
    while(times--){
        cin>>order>>side;
        if(order=='A'){
            if(side=='L'){
                cows.push_front(ncow++);
            }else{
                cows.push_back(ncow++);
            }
        }else if(order=='D'){
            int nums;
            cin>>nums;
            if(side=='L'){
                while(nums--){
                    cows.pop_front();
                }
            }else{
                while(nums--){
                    cows.pop_back();
                }
            }
        }
    }
    while(!cows.empty()){
        cout<<cows.front()<<endl;
        cows.pop_front();
    }