Compilare: main.cpp: In function 'bool is_ok(std::vector<std::pair<std::pair<long long int, long long int>, int> >&)': main.cpp:36:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 2; i + 1 < v.size(); i++) { ~~~~~~^~~~~~~~~~ main.cpp: In function 'int32_t main()': main.cpp:41:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("mission.in", "r", stdin); ^ main.cpp:42:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("mission.out", "w", stdout); ^