Compilare: user.cpp: In function ‘bool ver(int, int)’: user.cpp:29:71: warning: array subscript has type ‘char’ [-Wchar-subscripts] int pa=((s[i1].first[0]==s[i2].first[0])?0:nxt[i2][0][s[i2].first[0]]); ^ user.cpp:30:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<s[i1].first.size();i++){ ~^~~~~~~~~~~~~~~~~~~ user.cpp:32:36: warning: array subscript has type ‘char’ [-Wchar-subscripts] pa=nxt[i2][pa][s[i1].first[i+1]]; ^ user.cpp: In function ‘int main()’: user.cpp:52:36: warning: array subscript has type ‘char’ [-Wchar-subscripts] nxt[i][k][s[i].first[j]]=j; ^