Compilare: user.cpp: In function ‘int main()’: user.cpp:154:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("hacker2.in", "r", stdin); ^ user.cpp:155:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("hacker2.out", "w", stdout); ^ user.cpp:157:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &n, &m); ^ user.cpp:159:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d", &a, &b, &c); ^ user.cpp:172:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &a, &p); ^ user.cpp: In function ‘int lca(int, int, int&, int&)’: user.cpp:130:28: warning: array subscript is below array bounds [-Warray-bounds] dx = dx + dp2 [step][y]; ^ user.cpp:131:28: warning: array subscript is below array bounds [-Warray-bounds] dy = dy + dp2 [step][x]; ^