来自"NOCOW"

[编辑] 暴力型（0.484s）

var
  i,j,k,l,m,n,x,y,z,ww:longint;
begin
  readln(ww);
  case ww of
    0:writeln(1);
    2:writeln(10);
    4:writeln(670);
    6:begin
        for i:=0 to 9 do
          for j:=0 to 9 do
            for k:=0 to 9 do
              for n:=0 to 9 do
                for m:=0 to 9 do
                  for l:=0 to 9 do if i+j+k = l+m+n then inc(z);
      writeln(z);
    end;
    8:begin
      for i:=0 to 9 do
        for j:=0 to 9 do
          for k:=0 to 9 do
             for x:=0 to 9 do
               for y:=0 to 9 do
                 for n:=0 to 9 do
                   for m:=0 to 9 do
                     for l:=0 to 9 do if i+j+k+x = l+m+n+y then inc(z);
      writeln(z);
    end;
  end;
end.

[编辑] 交表型

VAR
  n:longint;
BEGIN
  readln(n);
    Case n of
      2:writeln(10);
      4:writeln(670);
      6:writeln(55252);
      8:writeln(4816030);
    END;
END.

[编辑] Dp型

这种弱智题目交表还不如写个Dp快,f[i,j]表示前i位值为j的有几种f[i,j]=sigma(f[i-1,j-k]) 0<=k<=9.

对了 楼上的你那个表打错了,输入0的时候输出因该是1(你可以这样理解前 0 div 2位的和为0,后0 div 2位的和也为0,所以有一种情况,这个东西确实难理解但确实应该输出1)

同学，正偶数是什么

program cao;
var
  f:array[0..4,-10..36] of longint;
  a,b,c,d,i,j,k,l,n,m,p,q,ans:longint;
 
begin
  read(n);
  n:=n shr 1;
  f[0,0]:=1;
  for i:=1 to n do
    for j:=0 to 36 do
      for k:=0 to 9 do
        inc(f[i,j],f[i-1,j-k]);
  for i:=0 to 36 do
    inc(ans,sqr(f[n,i]));
  writeln(ans);
end.

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弱弱的问一句，题目说Input contains a positive even integer not greater than 9. 楼上讨论输入是0的情况干什么？