I've solved this problem by using algorithm:

my pseudo code:
......
for (i=0; i<S; i++) {
   for (j=i; j<S and j<i+3; j++)
        if (sum_from_I_to_J(i,j) > j-i+1 + N) then begin
          out("NO");
          return(0);
        end;
   for (j=i+S-10; j<S and j>=i; j++)
        if (sum_from_I_to_J(i,j) > j-i+1 + N) then begin
          out("NO");
          return(0);
        end;
}
out("YES");
....
It was a test solution, I did't thought that I'll got AC.
I don't understand, why it works?

Thanks.

ps
sorry for my bad english.