bzoj 1037: [ZJOI2008]生日聚会Party （dp)

dp，但是要顺推容易点

const
  mm=;
var
  f:array[..,..,..,..]of longint;
  n,m,kk,now,sum,i,j,k1,k2:longint;

function max(x,y:longint):longint;
begin
  if x<y then exit(y);
  exit(x);
end;

begin
  readln(n,m,kk);
  now:=;
  f[now][,,]:=;
  f[now][,,]:=;
  for i:= to n+m- do begin
    fillchar(f[-now],sizeof(f[-now]),);
    for j:= to n do begin
      if (j>i) and (i-j>m) then continue;
      for k1:= to kk do
        for k2:= to kk do
          if f[now][j,k1,k2]> then begin
            if (k1<kk) and (j<n) then begin
              inc(f[-now][j+,k1+,max(k2-,)],f[now][j,k1,k2]);
              f[-now][j+,k1+,max(k2-,)]:=f[-now][j+,k1+,max(k2-,)] mod mm;
            end;
            if (k2<kk) and (i-j<m) then begin
              inc(f[-now][j,max(k1-,),k2+],f[now][j,k1,k2]);
              f[-now][j,max(k1-,),k2+]:=f[-now][j,max(k1-,),k2+] mod mm;
            end;
          end;
    end;
    now:=-now;
  end;
  sum:=;
  for i:= to kk do
    for j:= to kk do
      sum:=(f[now][n,i,j]+sum) mod mm;
  writeln(sum);
end.