View Compilation Error

0_0_26040582_24322.cpp: In function 'void dfsDP(int)':
0_0_26040582_24322.cpp:43:16: error: 'head' was not declared in this scope
     for (int i=head[x]; i; i=e[i].nxt){
                ^
0_0_26040582_24322.cpp:43:30: error: 'e' was not declared in this scope
     for (int i=head[x]; i; i=e[i].nxt){
                              ^
0_0_26040582_24322.cpp: In function 'void solve(int)':
0_0_26040582_24322.cpp:57:75: error: 'addEdge' was not declared in this scope
     for (int i=2; i<=n; i++) scanf("%d", &father[i]), addEdge(father[i], i);
                                                                           ^