Compilare: user.cpp: In function ‘void Insert_in_Apm(int)’: user.cpp:17:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < G[k].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:102:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < G[R].size(); ++j) ^ user.cpp:80:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in", "r", stdin); ^ user.cpp:81:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.out", "w", stdout); ^ user.cpp:82:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:86:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &a, &b, &c); ^