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)],
% Z8 }5 }, l7 c7 j% Z; i    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],
    HoldForm[(x1~s1~(x2~s2~x3))~s3~x4],
    HoldForm[x1~s1~(x2~s2~(x3~s3~x4))]};
  result = Union[result];
  For[i = 1, i <= Length[result], i++,
. ]0 q# f% M4 c8 L3 n1 D, ]   If[ReleaseHold[result[[i]]] == 24, Print[result[[i]], "=24"];
     (*Print[TreeForm[result[[i]],DirectedEdges->True]]*);];];]
  c8 ]$ u! i4 g# x: o& v1 N+ W
2 l; J8 Y& p$ P) Q7 h/ j' X. _$ k9 kfs[x1_, x2_, x3_, x4_] :=
Module[{result, s, sym, num, i, j}, Off[Divide::infy];
  Off[Part::partw];
  Off[Divide::indet];
4 s! |2 w5 r% J$ W- t  X  s = {Plus, Subtract, Times, Divide};
  sym = Flatten[
" M- T7 M6 ?1 s' K    Table[{s[[i]], s[[j]], s[[k]]}, {i, 4}, {j, 4}, {k, 4}], 2];
- `# m4 u/ G* q' I: A  sym = Union[sym];
/ h0 r. r+ A  ~. U2 t# }5 r  num = Permutations[{x1, x2, x3, x4}];
2 x% J. I: ~5 V; _  Do[f[num[[i, 1]], sym[[j, 1]], num[[i, 2]], sym[[j, 2]],
: Z8 [8 @5 u& W9 i    num[[i, 3]], sym[[j, 3]], num[[i, 4]]], {i, Length[num]}, {j,
& V, G3 T7 `. G+ e    Length[sym]}]]

; z* O, D. G% ^- S2 ~5 `% zfs[3, 3, 8, 8]