Language: C++

#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;

#define endl            "\n"
#define forn(i,n)       for(int i=0; i<n; i++)
#define ff              first
#define ss              second
#define int             long long
#define pb              push_back
#define mp              make_pair
#define pii             pair<int,int>
#define vi              vector<int>
#define mii             map<int,int>
#define pqb             priority_queue<int>
#define pqs             priority_queue<int,vi,greater<int> >
#define setbits(x)      __builtin_popcountll(x)
#define zrobits(x)      __builtin_ctzll(x)
#define mod             1000000007
#define inf             1e18
#define ps(x,y)         fixed<<setprecision(y)<<x
#define mk(arr,n,type)  type *arr=new type[n];
#define w(x)            int x; cin>>x; while(x--)
mt19937                 rng(chrono::steady_clock::now().time_since_epoch().count());

typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds;


void zeus()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
}

void subsetsUtil(vector<int>& A, vector<vector<int> >& res,
                 vector<int>& subset, int index)
{
    res.push_back(subset);
    for (int i = index; i < A.size(); i++) {

        // include the A[i] in subset.
        subset.push_back(A[i]);

        // move onto the next element.
        subsetsUtil(A, res, subset, i + 1);

        // exclude the A[i] from subset and triggers
        // backtracking.
        subset.pop_back();
    }

    return;
}

// below function returns the subsets of vector A.
vector<vector<int> > subsets(vector<int>& A)
{
    vector<int> subset;
    vector<vector<int> > res;

    // keeps track of current element in vector A;
    int index = 0;
    subsetsUtil(A, res, subset, index);

    return res;
}




int32_t main()
{
    zeus();

    int n; cin >> n;

    string s[n];

    stack<char> st[n];
    vector<pair<int, int>> type1, type2;
    int suma = 0, sumb = 0;

    forn(i, n) {
        cin >> s[i];
        stack<char> x;

        int a = 0, b = 0;
        forn(j, s[i].length()) {
            if (s[i][j] == '(') {
                suma++;
            }
            else {
                sumb++;
            }

            if (x.empty()) {
                x.push(s[i][j]);
                if (s[i][j] == '(') {
                    b++;
                }
                else {
                    a++;
                }
            }
            else if (s[i][j] == ')' && x.top() == '(') {
                x.pop();
                b--;
            }
            else {
                x.push(s[i][j]);
                if (s[i][j] == '(') {
                    b++;
                }
                else {
                    a++;
                }
            }
        }
        l[i] = mp(a, b);
        st[i] = x;
        if (a <= b) {
            type1.pb(mp(a, b));
        }
        else {
            type2.pb(mp(-1 * b, a));
        }
    }

    if (suma != sumb) {
        cout << "No" << endl;
        return 0;
    }

    sort(type1.begin(), type1.end());

    sort(type2.begin(), type2.end());

    int brack = 0;
    int flag = 1;
    forn(i, type1.size()) {
        brack -= type1[i].ff;
        if (brack < 0) {
            flag = 0;
            break;

        }
        brack += type1[i].ss;
    }
    if (flag != 0) {
        forn(i, type2.size()) {
            brack -= type2[i].ss;
            if (brack < 0) {
                flag = 0;
                break;
            }
            brack -= type2[i].ff;
        }
    }

    if (flag == 0) {
        cout << "No" << endl;
    }
    else {
        cout << "Yes" << endl;
    }




}





Compiler output:
a.cc: In function 'int32_t main()':
a.cc:123:9: error: 'l' was not declared in this scope
  123 |         l[i] = mp(a, b);
      |         ^