ac1141.pas

来自「这是在网络上搜集到的在东京大学的ACM上面解决的一些题目的源码」· PAS 代码 · 共 33 行

program tju1141;
const
  maxn=49;
var
  count:array[0..maxn]of qword;
  i,x,y,z:shortint;
function h(a:qword;b:byte):qword;
  var
    i:byte;
  begin
    h:=1;
    for i:=1 to b do
      h:=h*(a+i-1) div i;
  end;
begin
  count[0]:=1;
  for i:=1 to maxn do begin
    x:=0;z:=i-1;
    repeat
      if x<>z then inc(count[i],h(count[x],2)*count[z]) else inc(count[i],h(count[x],3));
      inc(x);dec(z,2);
    until z<0;
    for x:=0 to (i-1) div 3-1 do
      for y:=x+1 to (i-x-2) div 2 do
        inc(count[i],count[x]*count[y]*count[i-1-x-y]);
  end;

  repeat
    read(i);
    writeln(count[i]);
  until seekeof;
end.