Compilare: user.cpp: In function ‘void write(int, std::vector<int>)’: user.cpp:103:36: warning: format ‘%lu’ expects argument of type ‘long unsigned int’, but argument 2 has type ‘std::vector<int>::size_type {aka unsigned int}’ [-Wformat=] printf("%lu\n", answer.size()); ^ user.cpp: In function ‘void read_data(int&, int&, int*, int*, int*, int*)’: user.cpp:70:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:72:52: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x[i], &y[i], &cost[i]); ^