Compilare: user.cpp: In function ‘void DFS_2(int, int)’: user.cpp:81:31: warning: unused variable ‘index’ [-Wunused-variable] int son = edge.first, index = edge.second; ^ user.cpp: In function ‘void ReadInput()’: user.cpp:24:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); graph.resize(N + 1); ^ user.cpp:27:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int u, v; scanf("%d%d", &u, &v); ^