class Solution:
    def asteroidCollision(self, asteroids: List[int]) -> List[int]:
        stack = []
        for a in asteroids:
            while stack and a < 0 and stack[-1] > 0:
                diff = a + stack[-1]
                if diff < 0:
                    stack.pop()
                elif diff > 0:
                    a = 0
                else:
                    a = 0
                    stack.pop()
            if a:
                stack.append(a)
        return stack

class Solution:
    def asteroidCollision(self, asteroids: List[int]) -> List[int]:
        n = len(asteroids)
        j = -1

        for a in asteroids:
            while j >= 0 and asteroids[j] > 0 and a < 0:
                if asteroids[j] > abs(a):
                    a = 0
                    break
                elif asteroids[j] == abs(a):
                    j -= 1
                    a = 0
                    break
                else:
                    j -= 1
            if a:
                j += 1
                asteroids[j] = a

        return asteroids[:j + 1]