Compilare: user.cpp: In function ‘int get_id(Line)’: user.cpp:130:9: warning: unused variable ‘i’ [-Wunused-variable] int i, hsh; ^ user.cpp: In function ‘int main()’: user.cpp:181:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (same.size() == ((n - 1) * n) / 2) ^ user.cpp:190:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < medi.size(); i = j) { ^ user.cpp:191:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = i; j < medi.size(); j++) ^ user.cpp:151:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dmg.in","r",stdin); ^ user.cpp:152:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dmg.out","w",stdout); ^ user.cpp:154:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:156:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf", &P[i].x, &P[i].y); ^