Compilare: main.cpp: In function 'int main()': main.cpp:52:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<ans.size()-1;i++) ~^~~~~~~~~~~~~ main.cpp:31:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ciclueuler.in","r",stdin); ^ main.cpp:32:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ciclueuler.out","w",stdout); ^ main.cpp:34:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ main.cpp:38:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^