Compilare: user.cpp: In function ‘int cst(int, int)’: user.cpp:22:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(st < s.size()) { ^ user.cpp:23:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j < k && st+j < s.size(); j++) { ^ user.cpp:24:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[s[st+j]] ++; ^ user.cpp:25:24: warning: array subscript has type ‘char’ [-Wchar-subscripts] nel[s[st+j]] += (f[s[st+j]] > 1); ^ user.cpp:25:39: warning: array subscript has type ‘char’ [-Wchar-subscripts] nel[s[st+j]] += (f[s[st+j]] > 1); ^ user.cpp:27:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j < k && st+j < s.size(); j++) { ^ user.cpp:28:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[s[st+j]] --; ^ user.cpp:34:17: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(lua[z] > 0) { ^ user.cpp:35:32: warning: array subscript has type ‘char’ [-Wchar-subscripts] ch.push_back({lua[z], {0, z}}); ^ user.cpp:36:32: warning: array subscript has type ‘char’ [-Wchar-subscripts] ch.push_back({nel[z], {1, z}}); ^ user.cpp:38:12: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[z] = nel[z] = used[z] = 0; ^ user.cpp:38:21: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[z] = nel[z] = used[z] = 0; ^ user.cpp:38:31: warning: array subscript has type ‘char’ [-Wchar-subscripts] f[z] = nel[z] = used[z] = 0; ^ user.cpp: In function ‘int main()’: user.cpp:64:14: warning: array subscript has type ‘char’ [-Wchar-subscripts] lua[c]++; ^ user.cpp:65:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] lit += (lua[c]==1); ^