排列组合算法的javascript实现

从成员数为N的集合S中，选出M个元素，分别求其排列与组合结果集，即 A(N, M)与C(N, M)

function queue(arr, size){
  if(size > arr.length){ return;}
  var allResult = [];

  (function(arr, size, result){
    if(result.length == size){
      allResult.push(result);
    }else{
      for(var i =0 ,len = arr.length;i < len; i++){
        var newArr = [].concat(arr),
            curItem = newArr.splice(i,1);
        arguments.callee(newArr, size, [].concat(result,curItem));
      }
    }
  })(arr, size, []);

  return allResult;
}


function choose(arr, size ){
  var allResult = [];

  (function(arr, size, result){
    var arrLen = arr.length;
    if(size > arrLen){
      return;
    }
    if(size == arrLen){
      allResult.push([].concat(result, arr))
    }else{
      for(var i =0 ; i < arrLen; i++){
        var newResult = [].concat(result);
        newResult.push(arr[i]);

        if(size == 1){
          allResult.push(newResult);
        }else{
          var newArr = [].concat(arr);
          newArr.splice(0, i +　1);
          arguments.callee(newArr, size - 1, newResult);
        }
      }
    }
  })(arr, size, []);

  return allResult;
}

function showResult(result){
  console.log('The number of result sets: ' + result.length );
  for(var i=0 , len = result.length;i < len; i++){
    console.log(result[i]);
  }
}


var arr = ['姬光','王子', '三桂','科长'];

showResult(choose(arr, 4));
showResult(queue(arr, 4));

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