解决思路

贪心

  public boolean validStackSequences(int[] pushed,int[] poped){
        int N = pushed.length;
        Stack<Integer> stack = new Stack<>();
        int j = 0;
        for(int x:pushed){
            stack.push(x);
            //判断是否栈顶的元素为弹出的序列
            while (!stack.isEmpty() && j < N && stack.peek()==poped[j]){
                stack.pop();
                j++;
            }
        }
        return j == N;
    }