Compilare: user.cpp: In function ‘void update(int, int, int, int, int, int)’: user.cpp:47:9: warning: unused variable ‘mid’ [-Wunused-variable] int mid = (l + r) >> 1, lson = node * 2, rson = node * 2 + 1; ^ user.cpp: In function ‘void read()’: user.cpp:32:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("demolish.in", "r", stdin); ^ user.cpp:34:50: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d", &n, &m, &f, &dx, &dy); ^ user.cpp:36:77: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d", &v[i].x, &v[i].y, &v[i].z, &v[i].t, &v[i].c); ^ user.cpp: In function ‘void write()’: user.cpp:81:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("demolish.out", "w", stdout); ^