1001. Asteroid Collision

vector<int> asteroidCollision(vector<int> &asteroids) { // write your code here vector<int> res; for (int i = 0; i < asteroids.size(); ++i) { if (asteroids[i] > 0) { res.push_back(asteroids[i]); } else{ // less than 0 if (res.empty() || res.back() < 0) { res.push_back(asteroids[i]); } else if (res.back() <= -asteroids[i]) { if (res.back() < -asteroids[i]) { --i; } res.pop_back(); } } } return res; }