for j:=1 to ln(n)/ln(2)

    for i:=1 to n-(1 shl j)+1 do

       f[i,j]:=min(f[i,j-1],f[i+(1 shl (j-1),j-1];

f[l,r]:=min(f[l,j],f[r-(1 shl j)+1,j]; j=ln(r-l+1)/ln(2);

ln(n)/ln(2)=log(2,n);

Program lineup;
const
   maxn=50000;
   maxq=200000;
   maxh=1000000;
var
   n,q,i,j,l,r,k:longint;
   a:array[1..maxh] of longint;
   f,h:array[1..maxh,0..16] of longint;//f mintall h hightall
function min(a,b:longint):longint;
begin
   if a<b then exit(a) else exit(b);
end;
function max(a,b:longint):longint;
begin
   if a>b then exit(a) else exit(b);
end;

begin
   read(n,q);
   for i:=1 to n do
   begin
      read(a[i]);
      f[i,0]:=a[i];
      h[i,0]:=a[i];
   end;
   for j:=1 to trunc(ln(n)/ln(2)) do   //f[i,j]:=min(f[i,j-1],f[i+2^(j-1),j-1] i<=n-2^j
      for i:=1 to n-(1 shl j)+1 do
      begin
         f[i,j]:=min(f[i,j-1],f[i+1 shl (j-1),j-1]);
         h[i,j]:=max(h[i,j-1],h[i+1 shl (j-1),j-1]);
      end;

   for i:=1 to q do
   begin
      read(l,r);
      j:=(r-l+1);
      j:=trunc(ln(j)/ln(2));
      writeln(max(h[l,j],h[r-1 shl j +1,j])-min(f[l,j],f[r-1 shl j +1,j]));
   end;
end.