Compilare: user.cpp: In function ‘void write()’: user.cpp:99:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j, p; ^ user.cpp: In function ‘void read()’: user.cpp:24:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spider.in", "r", stdin); ^ user.cpp:25:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:29:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &H[i][j]); ^ user.cpp: In function ‘void write()’: user.cpp:100:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("spider.out", "w", stdout); ^ user.cpp: In function ‘void solve()’: user.cpp:90:62: warning: ‘j’ may be used uninitialized in this function [-Wmaybe-uninitialized] (px > i || (px == i && py > j)) )) ^