Compilare: user.cpp: In function ‘void Dfs(int)’: user.cpp:25:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < Gr[X].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:62:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < Cbc.size(); i++, printf("\n")) ^ user.cpp:63:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < Cbc[i].size(); j++) printf("%d ", Cbc[i][j]); ^ user.cpp:49:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biconex.in","r",stdin); ^ user.cpp:50:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biconex.out","w",stdout); ^ user.cpp:52:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &M); ^ user.cpp:54:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &X, &Y); ^