Compilare: main.cpp: In function 'int main()': main.cpp:20:41: warning: array subscript has type 'char' [-Wchar-subscripts] 20 | while(!dq.empty() and ch[dq.back()]>ch[i] and last[ch[dq.back()]-'a']!=dq.back()){ | ~~~~~~~^~ main.cpp:20:70: warning: array subscript has type 'char' [-Wchar-subscripts] 20 | while(!dq.empty() and ch[dq.back()]>ch[i] and last[ch[dq.back()]-'a']!=dq.back()){ | ~~~~~~~^~ main.cpp:21:26: warning: array subscript has type 'char' [-Wchar-subscripts] 21 | in[ch[dq.back()]-'a']=false; | ~~~~~~~^~ main.cpp:25:22: warning: array subscript has type 'char' [-Wchar-subscripts] 25 | in[ch[dq.back()]-'a']=true; | ~~~~~~~^~ main.cpp:28:26: warning: array subscript has type 'char' [-Wchar-subscripts] 28 | cout<<ch[dq.front()]; | ~~~~~~~~^~