Compilare: main.cpp: In function 'int main()': main.cpp:23:30: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::vector<ABC>::size_type {aka long unsigned int}' [-Wformat=] printf("%d\n", sol.size()); ^ main.cpp:24:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < sol.size(); i++) { ~~^~~~~~~~~~~~ main.cpp:11:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("armonica.in", "r", stdin); ^ main.cpp:12:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("armonica.out", "w", stdout); ^ main.cpp:13:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld\n", &b); ^