贴个算法，大佬们看是否有错，这两个用例是能过的
public static void main(String[] args) {
//int[] nums = new int[]{2, 1, 1, 2,2,1,4,4,4};//1
int[] nums = new int[]{2, 1, 2, 2, 1, 4, 4, 4};//2
Deque<Integer> st = new ArrayDeque<>();
int pre = -1;
for(int x : nums) {
if(pre == x)
continue;
if(st.isEmpty() || st.peek() != x) {
st.push(x);
} else {
while(!st.isEmpty() && st.peek() == x) {
st.pop();
}
pre = x;
}
}
while(!st.isEmpty()) {
System.out.println(st.pollFirst());
}
}
