what? 2010-10-26 03:42:00
点我顶贴
收藏
删除
var s,t,n,m:longint;
procedure f(x,y,k,x1,x2:longint);
begin
if (y>m)or(x1>n)or(x2>n) then exit;
if k=t then begin
if y=m then inc(s);
exit;end;
if x=0 then begin
f(1,y+1,k+1,x1+1,x2);
f(0,y,k+1,x1,x2+1);
end
else
if x=1 then begin
f(1,y,k+1,x1+1,x2);
f(0,y+1,k+1,x1,x2+1);
end;
end;
begin
read(n,m);
t:=n*2;
f(1,0,1,1,0);
f(0,0,1,0,1);
write(s);
end.