Compilare: user.cpp: In function ‘void match(std::vector<int>&, std::vector<int>&)’: user.cpp:30:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < small->size(); ++i) ^ user.cpp: In function ‘void dfs(int)’: user.cpp:48:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < up[y].size(); ++i) up[x] = min(up[x], up[y]); ^ user.cpp:49:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < down[y].size(); ++i) down[x] = max(down[x], down[y]); } ^