735.cpp

/**
 *    author:   vulkan
 *    created:  27.07.2021 06:36:32 PM
**/
#include <bits/stdc++.h>

using namespace std;

vector<int> asteroidCollision(vector<int> &asteroids) {
    int n = asteroids.size();
    deque<int> st;
    vector<int> ans;
    for (int i = 0; i <= n - 1; ++i) {
        if (asteroids[i] > 0) {
            st.push_back(asteroids[i]);
        } else {
            while (not st.empty() and st.back() < abs(asteroids[i])) {
                st.pop_back();
            }
            if (not st.empty()) {
                if (st.back() == abs(asteroids[i])) {
                    st.pop_back();
                }
            } else {
                ans.push_back(asteroids[i]);
            }
        }
    }

    while (not st.empty()) {
        ans.push_back(st.front());
        st.pop_front();
    }

    return ans;
}

int main(int argc, char const *argv[]) {
    int n;
    cin >> n;
    vector<int> asteroids(n);
    for (int i = 0; i <= n - 1; ++i) {
        cin >> asteroids[i];
    }

    vector<int> ans = asteroidCollision(asteroids);
    for (int x : ans) {
        cout << x << ' ';
    }

    return 0;
}