Compilare: user.cpp: In function ‘int solve(int)’: user.cpp:19:30: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (last[s[x + i]] == x + 1) ^ user.cpp:22:29: warning: array subscript has type ‘char’ [-Wchar-subscripts] frc[s[x + i]]++, last[s[x + i]] = x + 1; ^ user.cpp:22:47: warning: array subscript has type ‘char’ [-Wchar-subscripts] frc[s[x + i]]++, last[s[x + i]] = x + 1; ^ user.cpp:35:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (frec.size() > l) { ^ user.cpp:11:9: warning: unused variable ‘nr’ [-Wunused-variable] int nr = n / l; ^ user.cpp: In function ‘int main()’: user.cpp:46:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("smooth2.in", "r", stdin); ^ user.cpp:47:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("smooth2.out", "w", stdout); ^