Mathematica 24点程序！

cjilyy

f[x1_, s1_, x2_, s2_, x3_, s3_, x4_] :=
3 L! T( i+ [; L* E" ~9 @2 b Module[{result, i},
- X$ J. l3 K4 m, h( r  result = {HoldForm[(x1~s1~x2)~s2~(x3~s3~x4)],
8 R- Y2 `) ]: G" ]" z    HoldForm[x1~s1~(x2~s2~x3~s3~x4)],
3 n- B+ o: P' N! s4 |    HoldForm[x1~s1~x2~s2~(x3~s3~x4)],
7 b, x: X" D4 k3 m: V- T8 c    HoldForm[(x1~s1~x2~s2~x3)~s3~x4],
2 }0 z' P6 m2 o$ N* W    HoldForm[x1~s1~(x2~s2~x3)~s3~x4],
- O! ~' W- `2 \, u$ J) k* ~1 e* i/ l4 b    HoldForm[(x1~s1~(x2~s2~x3))~s3~x4],
    HoldForm[x1~s1~(x2~s2~(x3~s3~x4))]};
) g2 ?, k) V( A2 |. f  result = Union[result];
  n3 c2 r2 }2 s; h3 R1 d* r  For[i = 1, i <= Length[result], i++,
6 k5 d8 ?/ _  Y0 K   If[ReleaseHold[result[[i]]] == 24, Print[result[[i]], "=24"];
" V$ f! p) `2 e0 t) M8 u) M+ I     (*Print[TreeForm[result[[i]],DirectedEdges->True]]*);];];]
* r9 @4 d6 f1 ?6 \) X7 U
fs[x1_, x2_, x3_, x4_] :=
6 b/ ?& K' u6 W+ K; C" ] Module[{result, s, sym, num, i, j}, Off[Divide::infy];
- {) I, C9 I$ t: \' U  Off[Part::partw];
+ e- w% l1 R7 a  Off[Divide::indet];
! U4 T9 b0 M- Z/ t- z& ^! i3 x4 ~  s = {Plus, Subtract, Times, Divide};
1 E! }2 ]: d0 k) |5 J9 ?8 C3 G0 D  sym = Flatten[
3 t* n1 x$ g' |( x/ O5 M    Table[{s[[i]], s[[j]], s[[k]]}, {i, 4}, {j, 4}, {k, 4}], 2];
  sym = Union[sym];
  num = Permutations[{x1, x2, x3, x4}];
( V9 k3 a# p- M1 U  Do[f[num[[i, 1]], sym[[j, 1]], num[[i, 2]], sym[[j, 2]],
    num[[i, 3]], sym[[j, 3]], num[[i, 4]]], {i, Length[num]}, {j,
" [8 ]4 p, D; Z) c    Length[sym]}]]

9 ~' Q+ D+ b/ n/ m; q6 ^! W$ V4 X8 Tfs[3, 3, 8, 8]