Compilare: user.cpp: In function ‘int cost_min(char*)’: user.cpp:27:34: warning: array subscript has type ‘char’ [-Wchar-subscripts] dp[i][j] = a[s[i]][s[j]]; ^ user.cpp:27:40: warning: array subscript has type ‘char’ [-Wchar-subscripts] dp[i][j] = a[s[i]][s[j]]; ^ user.cpp:33:84: warning: array subscript has type ‘char’ [-Wchar-subscripts] dp[i][j] = min(dp[i][j], dp[i+1][k-1] + dp[k+1][j] + a[s[i]][s[k]]); ^ user.cpp:33:90: warning: array subscript has type ‘char’ [-Wchar-subscripts] dp[i][j] = min(dp[i][j], dp[i+1][k-1] + dp[k+1][j] + a[s[i]][s[k]]); ^