排列组合算法的javascript实现

命题：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)

js解法：

 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));

个人原创，如有漏洞或建议，请留言。