View Compilation Error

0_0_37781998_2395.cpp: In function 'void dfs(int, int)':
0_0_37781998_2395.cpp:30:12: error: 'check' was not declared in this scope
  if (check()) {
            ^
0_0_37781998_2395.cpp:32:3: error: 'flag' was not declared in this scope
   flag = 1;
   ^
0_0_37781998_2395.cpp:36:15: error: 'gu' was not declared in this scope
  if (cnt + gu() > x) return;
               ^
0_0_37781998_2395.cpp: In function 'int main()':
0_0_37781998_2395.cpp:49:16: error: 'n' was not declared in this scope
   scanf("%d", &n);
                ^