Compilare: main.cpp: In function 'bool bfs()': main.cpp:32:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<a[x].size();i++) ~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:61:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<a[n].size();i++) ~^~~~~~~~~~~~ main.cpp:47:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("maxflow.in","r",stdin); ^ main.cpp:48:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("maxflow.out","w",stdout); ^