Compilare: main.cpp: In function 'int main()': main.cpp:41:25: warning: array subscript has type 'char' [-Wchar-subscripts] ins[ x[i][j]].push_back( make_pair(i,j)); ^ main.cpp:52:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<ins[i].size();j++) ~^~~~~~~~~~~~~~ main.cpp:68:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<ins[1].size();i++) ~^~~~~~~~~~~~~~