Compilare: main.cpp: In function 'void solve()': main.cpp:30:16: warning: array subscript has type 'char' [-Wchar-subscripts] fr[s[i]]++; ^ main.cpp:31:19: warning: array subscript has type 'char' [-Wchar-subscripts] if(fr[s[i]] == 1) ^ main.cpp:36:25: warning: array subscript has type 'char' [-Wchar-subscripts] fr[Q.front()]--; ^ main.cpp:37:28: warning: array subscript has type 'char' [-Wchar-subscripts] if(fr[Q.front()] == 0) ^ main.cpp:41:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(Q.size() > lma) ~~~~~~~~~^~~~~ main.cpp:27:9: warning: 'prim' may be used uninitialized in this function [-Wmaybe-uninitialized] int prim; ^~~~