Compilare: user.cpp: In function ‘bool BF(int)’: user.cpp:42:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < g[nod].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:69:47: warning: narrowing conversion of ‘g[b].std::vector<_Tp, _Alloc>::size<Edge, std::allocator<Edge> >()’ from ‘std::vector<Edge>::size_type {aka unsigned int}’ to ‘int’ inside { } [-Wnarrowing] g[a].push_back({b, c, 0, 0, g[b].size()}); ^ user.cpp:70:53: warning: narrowing conversion of ‘(g[b].std::vector<_Tp, _Alloc>::size<Edge, std::allocator<Edge> >() + 1u)’ from ‘std::vector<Edge>::size_type {aka unsigned int}’ to ‘int’ inside { } [-Wnarrowing] g[a].push_back({b, INF, 0, cst, g[b].size() + 1}); ^ user.cpp:71:49: warning: narrowing conversion of ‘(g[a].std::vector<_Tp, _Alloc>::size<Edge, std::allocator<Edge> >() + 4294967294u)’ from ‘std::vector<Edge>::size_type {aka unsigned int}’ to ‘int’ inside { } [-Wnarrowing] g[b].push_back({a, 0, 0, 0, g[a].size() - 2}); ^ user.cpp:72:52: warning: narrowing conversion of ‘(g[a].std::vector<_Tp, _Alloc>::size<Edge, std::allocator<Edge> >() + 4294967295u)’ from ‘std::vector<Edge>::size_type {aka unsigned int}’ to ‘int’ inside { } [-Wnarrowing] g[b].push_back({a, 0, 0, -cst, g[a].size() - 1}); ^ user.cpp:74:43: warning: narrowing conversion of ‘g[1].std::vector<_Tp, _Alloc>::size<Edge, std::allocator<Edge> >()’ from ‘std::vector<Edge>::size_type {aka unsigned int}’ to ‘int’ inside { } [-Wnarrowing] g[0].push_back({1, x, 0, 0, g[1].size()}); ^ user.cpp:65:37: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d %d " ,&n,&m,&x); ^ user.cpp:68:49: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d %d %d " ,&a,&b,&c,&cst); ^