Compilare: user.cpp: In function ‘int main()’: user.cpp:62:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ans.size() != n) fo << "0\n"; ^ user.cpp:33:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("senat.in","r",stdin); ^ user.cpp:36:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n%d\n",&m,&n); ^ user.cpp:40:18: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(c+1); ^ /tmp/ccfMWG4e.o: In function `main': user.cpp:(.text.startup+0xa6): warning: the `gets' function is dangerous and should not be used.