Compilare: user.cpp: In function ‘void read()’: user.cpp:23:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hamster.in", "r", stdin); ^ user.cpp:24:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &q); ^ user.cpp:27:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &v[i]); ^ user.cpp: In function ‘void write()’: user.cpp:93:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hamster.out", "w", stdout); ^ user.cpp:98:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %lld", &k, &d); ^ user.cpp: In function ‘void solve()’: user.cpp:74:53: warning: ‘ry’ may be used uninitialized in this function [-Wmaybe-uninitialized] a.push(pq{a.top().x - 1, a.top().y, v[ry] - v[root(a.top().x - 1)]}); ^ user.cpp:75:78: warning: ‘rx’ may be used uninitialized in this function [-Wmaybe-uninitialized] a.push(pq{a.top().x, a.top().y + 1, v[root(a.top().y + 1)] - v[rx]}); ^