View Compilation Error

0_0_28948094_18413.cpp: In function 'void init()':
0_0_28948094_18413.cpp:24:9: error: 'head' was not declared in this scope
  memset(head,-1,sizeof(head));
         ^
0_0_28948094_18413.cpp: In function 'void add(ll, ll, ll)':
0_0_28948094_18413.cpp:31:17: error: 'head' was not declared in this scope
  side[cnt].next=head[x];
                 ^
0_0_28948094_18413.cpp: In function 'void dij(ll, ll)':
0_0_28948094_18413.cpp:49:12: error: 'head' was not declared in this scope
   for(ll i=head[now.id];i!=-1;i=side[i].next)
            ^
0_0_28948094_18413.cpp: In function 'int main()':
0_0_28948094_18413.cpp:71:26: error: 'm' was not declared in this scope
   scanf("%I64d%I64d",&n,&m);
                          ^