Compilare: user.cpp: In member function ‘bool comp::operator()(const std::pair<int, int>&, const std::pair<int, int>&) const’: user.cpp:28:13: warning: statement has no effect [-Wunused-value] a.s > b.s; ^ user.cpp:29:5: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘void Read()’: user.cpp:43:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &k); ^ user.cpp:45:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int u; scanf("%d", &u); ^ user.cpp:54:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &u, &v, &cost); ^