Mathematica 24点程序！

cjilyy

f[x1_, s1_, x2_, s2_, x3_, s3_, x4_] :=
Module[{result, i},
  result = {HoldForm[(x1~s1~x2)~s2~(x3~s3~x4)],
% G# B. }& ?- a2 D+ g2 q" ~" V- |) O    HoldForm[x1~s1~(x2~s2~x3~s3~x4)],
    HoldForm[x1~s1~x2~s2~(x3~s3~x4)],
; q' L* a5 s2 E: u( D4 u. s    HoldForm[(x1~s1~x2~s2~x3)~s3~x4],
% ]1 m1 s) G9 k6 o  p# _    HoldForm[x1~s1~(x2~s2~x3)~s3~x4],
    HoldForm[(x1~s1~(x2~s2~x3))~s3~x4],
    HoldForm[x1~s1~(x2~s2~(x3~s3~x4))]};
' Q7 _% d1 F. ^, g) p  result = Union[result];
; w- `0 y  L$ X- X$ d  For[i = 1, i <= Length[result], i++,
   If[ReleaseHold[result[[i]]] == 24, Print[result[[i]], "=24"];
4 O8 j' P5 x. J& Y2 g     (*Print[TreeForm[result[[i]],DirectedEdges->True]]*);];];]

fs[x1_, x2_, x3_, x4_] :=
  P* L8 c7 g# e) N/ l! b Module[{result, s, sym, num, i, j}, Off[Divide::infy];
  Off[Part::partw];
# Q% F3 J+ Z+ O  Off[Divide::indet];
  s = {Plus, Subtract, Times, Divide};
  sym = Flatten[
, K$ c# a" z. q    Table[{s[[i]], s[[j]], s[[k]]}, {i, 4}, {j, 4}, {k, 4}], 2];
: z1 j, |$ F/ K" h# @  sym = Union[sym];
1 q/ S( ]3 A9 K- K3 d; o  num = Permutations[{x1, x2, x3, x4}];
  Do[f[num[[i, 1]], sym[[j, 1]], num[[i, 2]], sym[[j, 2]],
' M9 f) u% K2 g9 A    num[[i, 3]], sym[[j, 3]], num[[i, 4]]], {i, Length[num]}, {j,
% ]) v6 b3 e4 P( Z5 V    Length[sym]}]]

0 i2 e3 y6 ~( n, h+ hfs[3, 3, 8, 8]