2022.7.13-----leetcode.735

 public int[] asteroidCollision(int[] asteroids) {
        Deque<Integer> s=new ArrayDeque<>();
        for(int i=0;i<asteroids.length;i++){
            if(s.isEmpty())
                s.add(asteroids[i]);
            else{
                int tmp=s.getLast();
            if(tmp>0){
                if(asteroids[i]>0)// Consistent with the nearest direction 
                    s.add(asteroids[i]);
               else{// Inconsistent direction 
                   while(tmp>0&&tmp<-asteroids[i]){
                       s.pollLast();// Find quality less than i, Planets with different directions 
                       if(s.isEmpty()) break;
                       tmp=s.getLast();
                   }
                   if(tmp==-asteroids[i]) s.pollLast();// Encounter planets with equal mass 
                   else if(tmp<0||s.isEmpty()) s.add(asteroids[i]);

               }
            }else
                s.add(asteroids[i]);// The previous planetary direction is left 
            }     
        }

        int[] ans=new int[s.size()];
        int idx=0;
        while(!s.isEmpty()){
            ans[idx++]=s.poll();
        }
        return ans;
    }