Compilare: main.cpp: In function 'int main()': main.cpp:29:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v.size();++i) ~^~~~~~~~~ main.cpp:8:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("alibaba.in","r",stdin); ^ main.cpp:9:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("alibaba.out","w",stdout); ^ main.cpp:11:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&k); ^ main.cpp:15:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%1d",&x); ^