解法一

✅ 完整代碼

評分結果(參考) ： AC (48ms, 352KB)

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

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int stk1_size=0, stk2_size=0;
    
    string op;
    while(cin >> op){
        if(op == "push"){
            cin.ignore(999, '\n');
            
            stk1_size++;
            cout << 1;
        }
        else{
            if(stk2_size > 0){
                stk2_size--;
                cout << 4;
                continue;
            }
            
            stk2_size += stk1_size;
            while(stk1_size > 0){ cout << 5; stk1_size--; }
            stk2_size--;
            cout << 4;
        }
    }
    
    return 0;
}