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)],
    HoldForm[x1~s1~(x2~s2~x3~s3~x4)],
    HoldForm[x1~s1~x2~s2~(x3~s3~x4)],
$ Y* q) o- n/ I+ v( S% A! V- s    HoldForm[(x1~s1~x2~s2~x3)~s3~x4],
0 i3 ^( H3 ~5 j  ]: d    HoldForm[x1~s1~(x2~s2~x3)~s3~x4],
    HoldForm[(x1~s1~(x2~s2~x3))~s3~x4],
) M# q4 V9 e# m4 J( V    HoldForm[x1~s1~(x2~s2~(x3~s3~x4))]};
4 [2 {) R9 c! N  result = Union[result];
- [/ U4 b" {) }2 d* L) i. y$ u  For[i = 1, i <= Length[result], i++,
   If[ReleaseHold[result[[i]]] == 24, Print[result[[i]], "=24"];
3 ?2 Z5 l/ U8 X$ g. k4 W& c& x     (*Print[TreeForm[result[[i]],DirectedEdges->True]]*);];];]

fs[x1_, x2_, x3_, x4_] :=
7 `4 @1 O2 b+ f% d Module[{result, s, sym, num, i, j}, Off[Divide::infy];
  Off[Part::partw];
2 f) K  p7 q5 J! o  Off[Divide::indet];
  s = {Plus, Subtract, Times, Divide};
  sym = Flatten[
    Table[{s[[i]], s[[j]], s[[k]]}, {i, 4}, {j, 4}, {k, 4}], 2];
8 R! i6 R" e8 H2 c9 w) J& N5 m  sym = Union[sym];
  num = Permutations[{x1, x2, x3, x4}];
  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,
% @$ K0 h7 L- s/ _    Length[sym]}]]

fs[3, 3, 8, 8]