Code

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

void solve(vector<int> &type, vector<int> &x) {
    int n = x.size();

    vector<vector<int>> occ_index(n + 1);
    vector<int> taken_count(n + 1);
    vector<bool> picked(n);

    bool possible = true;
    for (int i = 0; i < n; i++) {
        // Do a lazy pickup.
        if (type[i] == 1) {
            occ_index[x[i]].push_back(i);
        }

        if (type[i] == 2) {
            vector<int> &occurrences = occ_index[x[i]];
            if (occurrences.empty()) {
                possible = false;
                break;
            }

            int idx = occurrences.back();
            occurrences.pop_back();
            picked[idx] = true;

            // Add 1 to the range [idx, i]
            taken_count[idx] += 1;
            taken_count[i + 1] -= 1;
        }
    }

    // Convert the difference array to a prefix sum array.
    // This will retrieve the array after range queries.
    for (int i = 1; i < n; i++) {
        taken_count[i] += taken_count[i - 1];
    }

    if (!possible) {
        cout << "-1"
             << "\n";
        return;
    }

    int mx = -1;
    for (int i = 0; i < n; i++) {
        mx = max(mx, taken_count[i]);
    }
    cout << mx << "\n";

    for (int i = 0; i < n; i++) {
        if (type[i] == 1) {
            cout << picked[i] << " ";
        }
    }
    cout << "\n";
}

int main() {
    int n;
    cin >> n;

    vector<int> type(n), x(n);
    for (int i = 0; i < n; i++) {
        cin >> type[i] >> x[i];
    }

    solve(type, x);
    return 0;
}