Compilare: user.cpp: In function ‘bool value(const int&, node*)’: user.cpp:78:42: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (s->t2) return !v[st[t][s->t1]]; ^ user.cpp:79:35: warning: array subscript has type ‘char’ [-Wchar-subscripts] else return v[st[t][s->t1]]; ^ user.cpp:77:8: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if (s->t1 >= 0) ^ user.cpp: In function ‘bool backtrack(const char&)’: user.cpp:94:15: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (dd1[ch] != tt) return backtrack(ch+1); ^ user.cpp:98:17: warning: array subscript has type ‘char’ [-Wchar-subscripts] v[ch] = i; ^ user.cpp: In function ‘void query()’: user.cpp:108:21: warning: array subscript has type ‘char’ [-Wchar-subscripts] dd1[st[1][i]] = tt; ^ user.cpp:110:21: warning: array subscript has type ‘char’ [-Wchar-subscripts] dd2[st[2][i]] = tt; ^ user.cpp: In function ‘int main()’: user.cpp:127:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(task".in","r",stdin); ^ user.cpp:128:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(task".out","w",stdout); ^