Compilare: main.cpp: In function 'void solve()': main.cpp:49:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=1; j<lists[i].size(); ++j) bits[i].change(j, t[lists[i][j]]); ~^~~~~~~~~~~~~~~~ main.cpp: In function 'void read()': main.cpp:31:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("delay.in", "r", stdin); ^ main.cpp:32:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:33:43: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for(i=1; i<=n; ++i) scanf("%d", &t[i]); ^ main.cpp:36:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^ main.cpp:40:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &m); ^ main.cpp: In function 'void write()': main.cpp:54:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("delay.out", "w", stdout); ^ main.cpp:57:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &c, &x, &y); ^