Mathematica 24点程序！

cjilyy

f[x1_, s1_, x2_, s2_, x3_, s3_, x4_] :=
: `" M& G0 a+ o1 s Module[{result, i},
3 l* [5 ~3 {" P# A5 M8 p9 p+ T  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)],
    HoldForm[(x1~s1~x2~s2~x3)~s3~x4],
2 i; z$ V! O% ~  w1 _; J* T$ l% Q    HoldForm[x1~s1~(x2~s2~x3)~s3~x4],
    HoldForm[(x1~s1~(x2~s2~x3))~s3~x4],
    HoldForm[x1~s1~(x2~s2~(x3~s3~x4))]};
2 O3 A# [8 ~& t$ |3 T/ Y  result = Union[result];
  For[i = 1, i <= Length[result], i++,
0 d' _+ ]7 m, N/ a- N* b: Z0 d   If[ReleaseHold[result[[i]]] == 24, Print[result[[i]], "=24"];
     (*Print[TreeForm[result[[i]],DirectedEdges->True]]*);];];]

& |1 T. \0 j; E5 R. ifs[x1_, x2_, x3_, x4_] :=
Module[{result, s, sym, num, i, j}, Off[Divide::infy];
  Off[Part::partw];
  Off[Divide::indet];
  s = {Plus, Subtract, Times, Divide};
  sym = Flatten[
    Table[{s[[i]], s[[j]], s[[k]]}, {i, 4}, {j, 4}, {k, 4}], 2];
* h/ U$ A1 E) E  sym = Union[sym];
$ @) \) T! E, r; p1 k# l  Q4 s, p  num = Permutations[{x1, x2, x3, x4}];
0 J' @+ ~8 ~' T. f5 z$ m, K  Do[f[num[[i, 1]], sym[[j, 1]], num[[i, 2]], sym[[j, 2]],
' V0 m$ p: ?- T5 e0 b    num[[i, 3]], sym[[j, 3]], num[[i, 4]]], {i, Length[num]}, {j,
/ h3 o! _6 H% L; }0 _4 m/ H6 q    Length[sym]}]]
- I* v9 m6 _* }2 N( W; H' T0 P
fs[3, 3, 8, 8]