Compilare: user.cpp: In function ‘void solve()’: user.cpp:108:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < edges.size() ; ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:129:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("karb.out", "w", stdout); ^ user.cpp:130:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("karb.in", "r", stdin); ^ user.cpp:133:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m , &k); ^ user.cpp:138:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x, &y, &w); ^