Compilare: user.cpp: In function ‘void build_dp()’: user.cpp:23:26: warning: array subscript has type ‘char’ [-Wchar-subscripts] dp[it][i][i]=true; ^ user.cpp:30:54: warning: array subscript has type ‘char’ [-Wchar-subscripts] dp[x][i][i+k-1]|=(dp[it.first][i][j]&dp[it.second][j+1][i+k-1]); ^ user.cpp:30:74: warning: array subscript has type ‘char’ [-Wchar-subscripts] dp[x][i][i+k-1]|=(dp[it.first][i][j]&dp[it.second][j+1][i+k-1]); ^