题解 | 吐泡泡

#include <iostream>
#include<stack>
using namespace std;
long long n;
int main() {
    cin >> n;string s[n+2];
    for (int i=1;i<=n;++i){
        cin>>s[i];
    }
    for (int j = 1; j <=n; ++j) {
        int len=s[j].length();
        stack<char>a;
        for (int i=0;i<len;++i){
            if (a.empty()){
                a.push(s[j][i]);
            }else{
                if (a.size()==1){
                    if (s[j][i]=='o'){
                        if (a.top()=='o'){
                            a.pop();a.push('O');
                        }else{
                            a.push(s[j][i]);
                        }
                    }else{
                        if (a.top()=='O'){
                            a.pop();
                        }else{
                            a.push(s[j][i]);
                        }                    
                    }
                }else{
                    if (s[j][i]=='o'){
                        if (a.top()=='o'){
                            a.pop();
                            if (a.top()!='O')a.push('O');
                            else a.pop();
                        }else{
                            a.push(s[j][i]);
                        }
                    }else if(s[j][i]=='O'){
                        if (a.top()=='O'){
                            a.pop();
                        }else{
                            a.push(s[j][i]);
                        }                    
                    }
                }
            }
        }
        if (a.size()==0){
            cout<<"";
        }else{
            int len=a.size();
            char str[len+2];
            for (int i=len-1;i>=0;--i){
                str[i]=a.top();
                a.pop();
            }
            for (int i=0;i<len;++i){
                cout<<str[i];
            }
        }
        cout<<endl;
    }
}