Compilare: main.cpp: In function 'int main()': main.cpp:14:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<b.size();i++) frb[b[i]]++; ~^~~~~~~~~ main.cpp:14:41: warning: array subscript has type 'char' [-Wchar-subscripts] for(int i=0;i<b.size();i++) frb[b[i]]++; ^ main.cpp:15:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<a.size();i++) fra[a[i]]++; ~^~~~~~~~~ main.cpp:15:41: warning: array subscript has type 'char' [-Wchar-subscripts] for(int i=0;i<a.size();i++) fra[a[i]]++; ^ main.cpp:16:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<b.size();i++) ~^~~~~~~~~ main.cpp:17:20: warning: array subscript has type 'char' [-Wchar-subscripts] if(frb[b[i]]>fra[b[i]]) ^ main.cpp:17:30: warning: array subscript has type 'char' [-Wchar-subscripts] if(frb[b[i]]>fra[b[i]]) ^ main.cpp:21:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<a.size();i++) ~^~~~~~~~~ main.cpp:23:37: warning: array subscript has type 'char' [-Wchar-subscripts] while(!st.empty() and frb[ch] and ch<=st.top() and frb[st.top()]+1<=fra[st.top()]) ^ main.cpp:27:18: warning: array subscript has type 'char' [-Wchar-subscripts] if(frb[ch]) ^ main.cpp:29:19: warning: array subscript has type 'char' [-Wchar-subscripts] frb[ch]--; ^ main.cpp:31:15: warning: array subscript has type 'char' [-Wchar-subscripts] fra[ch]--; ^