Compilare: user.cpp: In function ‘int main()’: user.cpp:85:39: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(i = 0; i < N; ++i) ++nr[ s[i] ], B[ s[i] ].push(i+1); ^ user.cpp:85:50: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(i = 0; i < N; ++i) ++nr[ s[i] ], B[ s[i] ].push(i+1); ^ user.cpp:83:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d %d\n",&N,&M); ^ user.cpp:84:25: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%s\n",s); ^ user.cpp:88:36: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%c %c\n",&x,&y); ^