配列をグルーピングするパターンを全列挙するやつ(js)試作品（未完成）

grouping.js

G = {
  grouping: function(elements) {
    var i,j,k = 0;
    var groups= [];
    
    for (i = 1; i <= elements.length; i++) { // i:分割後のグループ数
      var grps = G.divideIntoGroups(elements, i);
      for (j = 0; j < grps.length; j++) {
        groups.push(grps[j]);
      }
    }
    
    return groups;
  },
  divideIntoGroups: function(elements, groupCount) {
    if (groupCount == 1) {
      return [elements];
    }
    
    var i,j,k = 0;
    var grps = [];
    var _grps = [];
    if (groupCount == 2) {
      for (i = 1; i < (elements.length / 2); i++) { // i:一番小さいグループの要素数
        _grps = G.makeTwoGroups(elements, i);
        for (j = 0; j < _grps.length; j++) {
          grps.push(_grps[j]);
        }
      }
      
      return grps;
    }
    /* FIXME どうやったらいいか思いつかない…
    for (i = 1; i < groupCount; i++) {
      
    }
    */
        
    return grps;
  },
  makeTwoGroups: function(elements, sizeOfSmallestGroup) {
    var i,j,k = 0;
    var firstGroups = [];
    var _grps = [];
    for (i = 0; i < elements.length; i++) {
      _grps = G.func(elements, i, sizeOfSmallestGroup);
      for (j = 0; j < _grps.length; j++) {
        firstGroups.push(_grps[j]);
      }
    }

    var grps = [];
    var secondGroup = [];
    for (i = 0; i < firstGroups.length; i++) {
      secondGroup = [];
      for (j = 0; j < elements.length; j++) {
        if (-1 == firstGroups[i].indexOf(elements[j])) {
          secondGroup.push(elements[j]);
        }
      }
      grps.push([firstGroups[i], secondGroup]);
    }
    
    return grps;
  },
  func: function(elements, fixedKey, length, grps){
    var i,j,k = 0;
    var grp = 0;
    var newGrps = [];
    grps = grps || [[]];
    for (i = 0; i < grps.length; i++) {
      grp = grps[i].slice(0);
      grp.push(elements[fixedKey]);
      newGrps.push(grp);
    }
    
    if (newGrps[0].length == length) {
      return newGrps;
    }
    
    var newGrps2 = [];
    var _grps = [];
    for (i = fixedKey + 1; i < elements.length; i++) {
      _grps = G.func(elements, i, length, newGrps);
      for (j = 0; j < _grps.length; j++) {
        newGrps2.push(_grps[j]);
      }
    }
      
    return newGrps2;
  }
};
//console.debug(G.func(['A','B','C'], 0, 3));
//console.debug(G.makeTwoGroups(['A','B','C','D'], 2));
console.debug(G.divideIntoGroups(['A','B','C'], 3));
//console.debug(G.grouping(['A','B','C']));