I think that there must be some 'X' one after another, because it is
said 'ai*X^(n-1)' like this for n=2:

0
X
X
*
*
1 --> I'm only not quite sure for this '1'
X
* --> and if there is no '1' this row also turns off
+
2
+


I have tried to write something but it sucked, so I got a Pascal
code and turned it to C++!

AC 0.02 sec

///////////////////////////////////////////////
// 1059

#include <stdio.h>

int i,n;

int main()
{
  scanf("%d",&n); puts("0");
  for (i=1;i<=n;i++)
    printf("X\n*\n%d\n+\n",i);
  //getch();
  return 0;
}
/////////////////////////////////////////////////