Compilare: user.cpp: In function ‘int build_heavy_paths(int)’: user.cpp:100:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (adjl[u].size() == (u == 0 ? 0 : 1)) { ^ user.cpp: In function ‘int main()’: user.cpp:154:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("heavypath.in", "r", stdin); ^ user.cpp:155:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("heavypath.out", "w", stdout); ^