题解 | 吐泡泡

1.注意要在&&前检查栈是否为空，!s1.empty();
2.连续消时要检查前面是否还有数据
#include <bits/stdc++.h>
using namespace std;
int main()
{
    int T;
    cin>>T;
    while(T--)
    {
        string str;
        cin>>str;
        stack<char>s1;
        for(int i=0;i<str.size();i++)
        {
            if(s1.empty()||s1.top()!=str[i])
            {
                s1.push(str[i]);
            }
            else if(s1.top()=='o'&&str[i]=='o')
            {
                s1.pop();
                if(!s1.empty()&&s1.top()=='O')
                {
                    s1.pop();
                }
                else if((!s1.empty()&&s1.top()=='o')||s1.empty())
                {
                    s1.push('O');
                }
            }
            else if(s1.top()=='O'&&str[i]=='O')
            {
                s1.pop();
            }
        }
        string str2="";
        while(!s1.empty())
        {
            str2+=s1.top();
            s1.pop();
        }
        reverse(str2.begin(),str2.end());
        cout<<str2<<endl;
    }
}