Pop Sequence

Given a stack which can keep M numbers at most. Push N numbers in the order of 1, 2, 3, ..., N and pop randomly. You are supposed to tell if a given sequence of numbers is a possible pop sequence of the stack. For example, if M is 5 and N is 7, we can obtain 1, 2, 3, 4, 5, 6, 7 from the stack, but not 3, 2, 1, 7, 5, 6, 4.

Input Specification:

Each input file contains one test case. For each case, the first line contains 3 numbers (all no more than 1000): M (the maximum capacity of the stack), N (the length of push sequence), and K (the number of pop sequences to be checked). Then K lines follow, each contains a pop sequence of N numbers. All the numbers in a line are separated by a space.

Output Specification:

For each pop sequence, print in one line "YES" if it is indeed a possible pop sequence of the stack, or "NO" if not.

Sample Input:

5 7 5
1 2 3 4 5 6 7
3 2 1 7 5 6 4
7 6 5 4 3 2 1
5 6 4 3 7 2 1
1 7 6 5 4 3 2

Sample Output:

YES
NO
NO
YES
NO

#include <bits/stdc++.h>
using namespace std;

int main(){
    int m,n,k;
    cin>>m>>n>>k;
    while(k--){
        stack<int> s;
        int i=1;
        int a[1005],f=0;
        for(int j=0;j<n;j++){
            cin>>a[j];
            if(f)continue;
            while(i<=n+1){
                if(s.size()==m){
                    if(s.top()!=a[j])f=1;
                    else s.pop();
                    break;
                }
                else if(s.size()<m){
                    if(s.empty())s.push(i++);
                    else{
                        if(s.top()==a[j]){
                            s.pop();break;
                        }
                        else if(s.top()<a[j])
                            s.push(i++);
                        else if(s.top()>a[j]){
                            f=1;break;
                        }
                    }
                }
            }

        }

        if(f)cout<<"NO"<<endl;
        else{
            if(s.empty())cout<<"YES"<<endl;
            else cout<<"NO"<<endl;
        }


    }
}

卡了一会儿，出现错误现象：数据没输完却输出了完整数量的答案，找了一会错，发现自己f=1后立刻将整个程序break掉了，没让数据输完。