View Compilation Error

0_0_18442362_14681.cpp: In function 'void solve(int)':
0_0_18442362_14681.cpp:41:27: error: 'memset' was not declared in this scope
  memset(F[x],0,sizeof F[x]);
                           ^
0_0_18442362_14681.cpp: In function 'int main()':
0_0_18442362_14681.cpp:63:22: error: 'memset' was not declared in this scope
   memset(V,0,sizeof V);
                      ^