Asteroid Collision

def asteroidCollision(asteroids):
    row = list(asteroids)
    while True:
        # A crash happens where a right-mover is directly followed by a left-mover.
        hit = -1
        for i in range(len(row) - 1):
            if row[i] > 0 and row[i + 1] < 0:
                hit = i
                break
        if hit == -1:
            return row
        right, left = row[hit], -row[hit + 1]
        if right > left:
            del row[hit + 1]
        elif right < left:
            del row[hit]
        else:
            del row[hit:hit + 2]

def asteroidCollision(asteroids):
    survivors = []  # the row so far, after every crash it caused
    for rock in asteroids:
        alive = True
        # Only a left-mover can hit something: a right-mover on top of the stack.
        while alive and rock < 0 and survivors and survivors[-1] > 0:
            top = survivors[-1]
            if top < -rock:
                survivors.pop()        # the right-mover is smaller and explodes
            elif top == -rock:
                survivors.pop()        # same size: both explode
                alive = False
            else:
                alive = False          # the right-mover is bigger: the new one explodes
        if alive:
            survivors.append(rock)
    return survivors