Compilare: user.cpp: In function ‘void ext_comp(int, int, int)’: user.cpp:54:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < V[x].size(); ++ i) ~~^~~~~~~~~~~~~ user.cpp:63:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < V[x].size(); ++ i) ~~^~~~~~~~~~~~~ user.cpp: In function ‘void dfs(int)’: user.cpp:90:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < V[x].size(); ++ i) ~~^~~~~~~~~~~~~ user.cpp: In function ‘void read()’: user.cpp:36:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:39:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &c[i]); ^ user.cpp:43:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^