Compilare: user.cpp: In function ‘void back(int)’: user.cpp:24:17: warning: array subscript has type ‘char’ [-Wchar-subscripts] val[a[k + 1]] = 0; ^ user.cpp:26:17: warning: array subscript has type ‘char’ [-Wchar-subscripts] val[a[k + 1]] = 1; ^ user.cpp: In function ‘int solve()’: user.cpp:89:50: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(s[p] >= 'a' && s[p] <= 'z') r = val[s[p++]]; ^ user.cpp: In function ‘int main()’: user.cpp:32:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("logic.in", "r", stdin); ^ user.cpp:33:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("logic.out", "w", stdout); ^ user.cpp:34:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:36:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s1); ^ user.cpp:37:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", s2); ^