Compilare: user.cpp: In function ‘void df(int)’: user.cpp:15:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[nod].size(); ++i) ^ user.cpp: In function ‘void dfup(int)’: user.cpp:36:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[nod].size(); ++i) ^ user.cpp: In function ‘void df2(int)’: user.cpp:51:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[nod].size(); ++i) ^ user.cpp:73:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[nod].size(); ++i) ^ user.cpp:84:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<q[nod].size(); ++i) ^ user.cpp: In function ‘void dfdown(int)’: user.cpp:110:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[nod].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:121:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("treespotting.in", "r", stdin); ^ user.cpp:122:45: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("treespotting.out", "w", stdout); ^ user.cpp:124:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:128:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a, &b); ^ user.cpp:139:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a, &b); ^