Mathematica 24点程序！

cjilyy

f[x1_, s1_, x2_, s2_, x3_, s3_, x4_] :=
3 l& l- }- J; Z( M' s4 ]& J: z% C Module[{result, i},
5 ~, [4 D% y9 G- G  result = {HoldForm[(x1~s1~x2)~s2~(x3~s3~x4)],
+ R7 a3 H, {" k: I' h7 p! }8 T    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],
; C4 n5 d/ v1 I/ d    HoldForm[x1~s1~(x2~s2~(x3~s3~x4))]};
9 X8 k  U% ]: q7 V: V7 g  f$ Y5 C  result = Union[result];
  For[i = 1, i <= Length[result], i++,
   If[ReleaseHold[result[[i]]] == 24, Print[result[[i]], "=24"];
* h% y" T$ \' U2 n* j! Q( f     (*Print[TreeForm[result[[i]],DirectedEdges->True]]*);];];]

: B# U7 a5 k9 k6 Hfs[x1_, x2_, x3_, x4_] :=
Module[{result, s, sym, num, i, j}, Off[Divide::infy];
  Off[Part::partw];
: v8 @' w# F" f0 @; l- j9 ]# P7 R  Off[Divide::indet];
  s = {Plus, Subtract, Times, Divide};
  sym = Flatten[
" o5 L% {/ f: g+ N    Table[{s[[i]], s[[j]], s[[k]]}, {i, 4}, {j, 4}, {k, 4}], 2];
  sym = Union[sym];
* F$ M7 v7 d3 j7 k7 w  m: D) A  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,
& X  e, [0 I( I8 A    Length[sym]}]]

7 Y& w1 g2 q$ b% Y) Jfs[3, 3, 8, 8]