View Compilation Error

0_0_2869296_10548.cpp: In member function `void Graph::Insert(int, int, int, int)':
0_0_2869296_10548.cpp:59: error: `find' undeclared (first use this function)
0_0_2869296_10548.cpp:59: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_2869296_10548.cpp: In function `int main()':
0_0_2869296_10548.cpp:126: error: `find' undeclared (first use this function)