Compilare: main.cpp: In member function 'std::pair<long long int, long long int> Graph::dfs(Long, Long, Long)': main.cpp:65:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(Long &i = nextEdge[u]; i < adj[u].size(); i++){ ~~^~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:199:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fmcm.in", "r", stdin); ^ main.cpp:200:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fmcm.out", "w", stdout); ^ main.cpp: In member function 'std::pair<long long int, long long int> Graph::minCostFlow(Long, Long, Long)': main.cpp:134:4: warning: 'negaCycle' may be used uninitialized in this function [-Wmaybe-uninitialized] if(cur == y){ ^~ main.cpp:155:8: note: 'negaCycle' was declared here Long negaCycle; //negative cycle flag ^~~~~~~~~