View Compilation Error

0_0_29541888_13982.cpp: In function 'int main()':
0_0_29541888_13982.cpp:17:29: error: 'a' was not declared in this scope
   memset(vis,0,sizeof(vis));a-
                             ^
0_0_29541888_13982.cpp:18:3: error: expected primary-expression before 'for'
   for(int i=0;i<n;i++)
   ^
0_0_29541888_13982.cpp:18:15: error: 'i' was not declared in this scope
   for(int i=0;i<n;i++)
               ^