View Compilation Error

0_0_19632915_8091.cpp:4:1: error: '_int64' does not name a type
 _int64 a[maxn];
 ^
0_0_19632915_8091.cpp: In function 'int main()':
0_0_19632915_8091.cpp:12:10: error: 'a' was not declared in this scope
   memset(a,0,sizeof(a));
          ^