View Compilation Error

0_0_33820218_3532.cpp: In function 'void dfs(int)':
0_0_33820218_3532.cpp:33:7: error: 'a' was not declared in this scope
   if (a[v] > mx) mx = a[v], mxid = v;
       ^
0_0_33820218_3532.cpp:34:7: error: 'a' was not declared in this scope
   if (a[v] < mn) mn = a[v], mnid = v;
       ^
0_0_33820218_3532.cpp: In function 'int main()':
0_0_33820218_3532.cpp:49:42: error: 'a' was not declared in this scope
   for (register int i = 1; i <= n; i+=1) a[i] = gi <long long> ();
                                          ^
0_0_33820218_3532.cpp:51:7: error: 'a' was not declared in this scope
   if (a[1] > 0) sum1 += a[1], vis1[1] = true;
       ^
0_0_33820218_3532.cpp:56:20: error: 'a' was not declared in this scope
    if (!vis1[i] && a[i] > mx1) mx1 = a[i];
                    ^
0_0_33820218_3532.cpp:57:20: error: 'a' was not declared in this scope
    if (!vis2[i] && a[i] < mn1) mn1 = a[i];
                    ^