P1241 68分求调

#include <bits/stdc++.h>

using namespace std;

stack <pair <char, int> > st;
unordered_map <int, bool> mp;

int main()
{
    string exp;

    cin>>exp;

    for (int i = 0; i < exp.length(); i ++)
    {
        if (exp[i] == '(' || exp[i] == '[')
        {
            st.push(make_pair(exp[i], i));
        }
        if (exp[i] == ')')
        {
            if (st.empty())
            {
                st.push(make_pair(exp[i], i));
                continue;
            }
            else if (st.top().first == '(')
            {
                st.pop();
            }
            else
            {
                st.push(make_pair(exp[i], i));
            }
        }
        if (exp[i] == ']')
        {
            if (st.empty())
            {
                st.push(make_pair(exp[i], i));
                continue;
            }
            else if (st.top().first == '[')
            {
                st.pop();
            }
            else
            {
                st.push(make_pair(exp[i], i));
            }
        }
    }

    while (!st.empty())
    {
        //cout<<st.top().first;
        mp[st.top().second] = true;
        st.pop();
    }

    for (int i = 0; i < exp.length(); i ++)
    {
        if (mp[i] == true)
        {
            if (exp[i] == '(')
            {
                cout<<exp[i];
                cout<<")";
            }
            else if (exp[i] == ')')
            {
                cout<<"(";
                cout<<exp[i];
            }
            else if (exp[i] == '[')
            {
                cout<<exp[i];
                cout<<"]";
            }
            else if (exp[i] == ']')
            {
                cout<<"[";
                cout<<exp[i];
            }
        }
        else
        {
            cout<<exp[i];
        }
    }
    return 0;
}