Compilare: user.c: In function ‘main’: user.c:23:5: warning: array subscript has type ‘char’ [-Wchar-subscripts] d[i][i][s[i]] = 1; ^ user.c:31:11: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(d[j][k][s[j]] < 2 + d[j + 1][k - 1][l]) ^ user.c:32:13: warning: array subscript has type ‘char’ [-Wchar-subscripts] d[j][k][s[j]] = 2 + d[j + 1][k - 1][l]; ^ user.c:11:8: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result] fgets(s, MAXN + 2, in); ^