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)],
0 M. c2 E5 g# s    HoldForm[x1~s1~(x2~s2~x3~s3~x4)],
. y4 c( ~+ m7 }% E7 R' A: D    HoldForm[x1~s1~x2~s2~(x3~s3~x4)],
2 U- x  y1 g% {: R2 [    HoldForm[(x1~s1~x2~s2~x3)~s3~x4],
/ w, \/ C/ n. F    HoldForm[x1~s1~(x2~s2~x3)~s3~x4],
, Y8 a' V( S1 S) W6 m    HoldForm[(x1~s1~(x2~s2~x3))~s3~x4],
' A! ]4 o! D$ C7 R    HoldForm[x1~s1~(x2~s2~(x3~s3~x4))]};
8 e. ]4 |6 H( i3 y, P  result = Union[result];
* l/ G! Y  z+ D: I& }, B6 k2 H& O  For[i = 1, i <= Length[result], i++,
/ H) c; V& D4 f( N: k% C1 m9 l   If[ReleaseHold[result[[i]]] == 24, Print[result[[i]], "=24"];
0 Q, R. H2 b. G) x) A3 }. t- }     (*Print[TreeForm[result[[i]],DirectedEdges->True]]*);];];]

( [! o0 h6 t- n9 ]  L) k$ ]fs[x1_, x2_, x3_, x4_] :=
Module[{result, s, sym, num, i, j}, Off[Divide::infy];
" }$ g* E/ s4 n( R$ x  Off[Part::partw];
  Off[Divide::indet];
  s = {Plus, Subtract, Times, Divide};
  sym = Flatten[
. R# p; }) b9 G  C& D8 e    Table[{s[[i]], s[[j]], s[[k]]}, {i, 4}, {j, 4}, {k, 4}], 2];
  sym = Union[sym];
+ [/ k. c0 w9 U* ^& T% Y/ @  num = Permutations[{x1, x2, x3, x4}];
$ u- q5 c7 o' E; Z2 H7 T  Do[f[num[[i, 1]], sym[[j, 1]], num[[i, 2]], sym[[j, 2]],
2 Z3 `% u. H  N- ]    num[[i, 3]], sym[[j, 3]], num[[i, 4]]], {i, Length[num]}, {j,
    Length[sym]}]]
/ K+ J- Y# i% T: p) q, J6 A- Q
- b, Z' O3 F; F' d' r' a: P8 p2 Afs[3, 3, 8, 8]