Compilare: user.cpp: In function ‘int main()’: user.cpp:33:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<A[l].size()&&!ok; ++j){ ^ user.cpp:38:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<A[l].size();++j) ^ user.cpp:11:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("flori.in", "r", stdin); ^ user.cpp:12:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("flori.out", "w", stdout); ^ user.cpp:13:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^ user.cpp:19:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^