一只题解

#include<iostream>
#include<vector>
using namespace std;
vector<int>v;
int main(){
    int n;
    cin>>n;
    int m=n;
    for(int i=1;i<=n;i++){
        char a;
        int b;
        cin>>a;
        if(a=='I'){
            cin>>b;
            v.push_back(b);
        }
        else {
            v.pop_back();
            m--;
        }
    }
    for(int i=0;i<m-1;i++)cout<<v[i]<<" ";
}