bubbleSort: function(arr){
    for(var i = 0; i < arr.length - 1; i++){
        for(var j = 1; j < arr.length - 2; j++){
            if(arr[j-1] > arr[j]){
                temp = arr[j];
                arr[j] = arr[j-1];
                arr[j-1] = temp;
            }
        }
    }
    return arr;
},

    quickSort: function(arr){
        if(arr.length < 2) return arr;
        var middleIndex = Math.floor(arr.length / 2);
        var middleValue = arr.splice(middleIndex,1)[0];

        var left = [];
        var right = [];
        for(var i = 0; i < arr.length; i++){
            if(arr[i] < middleValue){
                left.push(arr[i]);
            }else{
                right.push(arr[i]);
            }
        }
        return this.quickSort(left).concat(middleValue,this.quickSort(right));
}

insertionSort(arr) {
var len = arr.length;
var preIndex, current;
for (var i = 1; i < len; i++) {
    preIndex = i - 1;
    current = arr[i];
    while(preIndex >= 0 && arr[preIndex] > current) { // 找位置
        arr[preIndex + 1] = arr[preIndex];
        preIndex--;
    }
    arr[preIndex + 1] = current; // 插入
}
return arr;
}

shellSort: function(arr) {
    var len = arr.length;
for (var fraction = Math.floor(len / 2); fraction > 0;
        fraction = Math.floor(fraction / 2)) {
  for (var i = fraction; i < len; i++) {
    for (var j = i - fraction; j >= 0 &&
            arr[j] > arr[fraction + j]; j -= fraction) {
      var temp = arr[j];
      arr[j] = arr[fraction + j];
    arr[fraction + j] = temp;
    }
  }
}
  return arr;
}

selectionSort: function(arr){
    var minIndex, temp;
    for(var n = 0; n < arr.length - 1; n++){
        minIndex = n;
        for(var i = n + 1; i < arr.length; i++ ){
          if(arr[i] < arr[minIndex]){
              minIndex = i;
          }
      };
        temp = arr[minIndex];
        arr[minIndex] = arr[n];
        arr[n] = temp;
    }
    return arr;
}

binarySearch(data, dest){
  var h = data.length - 1,
      l = 0;
  while(l <= h){
    var m = Math.floor((h + l) / 2);
  if(data[m] == dest){
  return m;
}
  if(dest > data[m]){
  l = m + 1;
}else{
  h = m - 1;
}
}
  return false;
}

factorial(num){
  if(num == 0){
    return 1;
  }else if(num == 1){
    return 1;
  }else{
    return num * this.factorial(num-1);
  }
}