View Compilation Error

0_0_18835242_7165.cpp:6:17: error: array bound is not an integer constant before ']' token
 long long a[maxn];
                 ^
0_0_18835242_7165.cpp: In function 'void init()':
0_0_18835242_7165.cpp:15:4: error: 'a' was not declared in this scope
    a[j] += i;
    ^
0_0_18835242_7165.cpp:18:6: error: 'a' was not declared in this scope
   if(a[i]<=1000) sum[i] = 1;
      ^