Compilare: user.cpp: In function ‘int main()’: user.cpp:55:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<G[x].size(); i++){ ^ user.cpp:38:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("atac2.in", "r", stdin); ^ user.cpp:39:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("atac2.out", "w", stdout); ^ user.cpp:41:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &n, &m,&U, &X); ^ user.cpp:42:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i=1; i<=U; i++) scanf("%d", &u[i]); ^ user.cpp:44:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^