Compilare: user.cpp: In function ‘int main()’: user.cpp:45:38: warning: array subscript has type ‘char’ [-Wchar-subscripts] for (int i = 1;i <= n;++i) v[s[i]].push(i); ^ user.cpp:41:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bignumber.in","r",stdin); ^ user.cpp:42:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n",&n,&k); ^ user.cpp:43:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s+1); ^ user.cpp:46:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bignumber.out","w",stdout); ^ /tmp/ccvwFQzF.o: In function `main': user.cpp:(.text.startup+0x55): warning: the `gets' function is dangerous and should not be used.