Compilare: user.cpp: In function ‘void df(int)’: user.cpp:15:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0;j<v[x].size();j++) ^ user.cpp: In function ‘int main()’: user.cpp:25:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("easygraph.in","r",stdin); ^ user.cpp:26:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("easygraph.out","w",stdout); ^ user.cpp:27:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t); ^ user.cpp:35:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); ^ user.cpp:36:62: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (i=1;i<=n;i++) scanf("%d",&cost[i]),dp[i]=cost[i]; ^ user.cpp:38:61: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&x,&y),v[x].push_back(y),grad[y]++; ^