Compilare: user.cpp: In function ‘void royfloyd(std::vector<std::vector<int> >)’: user.cpp:21:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < graph.size(); ++k) { ^ user.cpp:22:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < graph.size(); ++i) { ^ user.cpp:23:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < graph.size(); ++j) { ^ user.cpp:31:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < dp.size(); ++i) { ^ user.cpp:32:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < dp.size(); ++j) { ^ user.cpp:20:13: warning: unused variable ‘inf’ [-Wunused-variable] const int inf = 1 << 30; ^