View Compilation Error

0_0_33856303_31490.cpp: In member function 'void HashMap::init()':
0_0_33856303_31490.cpp:74:3: error: 'seed' was not declared in this scope
   seed=++rid;
   ^
0_0_33856303_31490.cpp:75:10: error: 'head' was not declared in this scope
   memset(head, -1, sizeof head);
          ^
0_0_33856303_31490.cpp: In member function 'void HashMap::add(int, VI&, int)':
0_0_33856303_31490.cpp:81:15: error: 'head' was not declared in this scope
   for(int e = head[u]; ~e; e=nxt[e]) {
               ^
0_0_33856303_31490.cpp:93:12: error: 'head' was not declared in this scope
   nxt[E] = head[u]; to[E] = now; dp[E] = 0; head[u] = E++;
            ^
0_0_33856303_31490.cpp: In member function 'int HashMap::calc()':
0_0_33856303_31490.cpp:101:14: error: 'head' was not declared in this scope
    for(int e=head[i]; ~e; e=nxt[e]) {
              ^