Compilare: user.cpp: In function ‘void dfs(int, int, int, int)’: user.cpp:59:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (nr = 1; (1 << nr) < v.size(); nr++) ^ user.cpp: In function ‘int main()’: user.cpp:83:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("atac.in","r",stdin); ^ user.cpp:84:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("atac.out","w",stdout); ^ user.cpp:87:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &n, &m, &p); ^ user.cpp:90:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &cost); ^ user.cpp:95:63: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d %d", &node1, &node2, &A, &B, &C, &D); ^