View Compilation Error

0_0_38070473_5050.cpp: In function 'long long int Func(long long int, long long int)':
0_0_38070473_5050.cpp:72:26: error: 'reverse' was not declared in this scope
  reverse(arr+1, arr+1+tot);
                          ^
0_0_38070473_5050.cpp:76:28: error: 'memset' was not declared in this scope
  memset(vis, 0, sizeof(vis));
                            ^