从大到小一个个放，试想现在该放第i个，放两边就增加一对说话者，放中间就增加两个说话者，所以f[i,j]:=(f[i-1,j-2]*(i-2)+f[i-1,j-1]<<1)mod 9937;


Problem: 3934  User: lydliyudong 
Memory: 924K  Time: 0MS 
Code Length: 299B
Language: Pascal  Result: Accepted 



var
 f:array[0..80,-1..157]of longint;
 n,m,i,j:longint;
begin
 f[1,0]:=1;
 for i:=2 to 80 do
  for j:=i-1 to i<<1-3 do
   f[i,j]:=(f[i-1,j-2]*(i-2)+f[i-1,j-1]<<1)mod 9937;
 read(n,m);
 while n+m<>0 do
  begin
   if m>157 then writeln(0) else writeln(f[n,m]);
   read(n,m);
  end;
end.

• Orz!!!! (574) 123234345 2011-09-23 15:26:27