Pascal深搜做法，第二个点TLE，90分。。。

var
  n,m,i,j,sum,max,maxx:longint;
  a,f:array[0..99,0..100] of longint;
  b:array[1..4] of longint=(-1,0,1,0);
  c:array[1..4] of longint=(0,-1,0,1);
function pk(x,y:longint):longint;
var i:longint;
begin
  if f[x,y]=0 then exit;
  for i:=1 to 4 do
   if (a[x+b[i],y+c[i]]<a[x,y])and(f[x+b[i],y+c[i]]=-1) then
     begin
      inc(sum);
      f[x+b[i],y+c[i]]:=1;
      if sum>max then max:=sum;
       pk(x+b[i],y+c[i]);
        f[x+b[i],y+c[i]]:=-1;
        dec(sum);
       end;
 end;
begin
  readln(n,m);
  fillchar(f,sizeof(f),0);
  for i:=1 to n do
    for j:=1 to m do begin read(a[i,j]);f[i,j]:=-1;end;
   for i:=n downto 1 do
     for j:=1 to m do
      begin
       sum:=1;max:=1;
        pk(i,j);
         if max>maxx then maxx:=max;
     end;
  writeln(maxx);
end.

。。。