JSを使用してソートアルゴリズムを実装する

function bubbleSort(arr) {  var len = arr.length;  for (var i = 0; i < len; i++) {    for (var j = 0; j < len - 1 - i; i++) {         // 相邻元素两两对比，元素交换
        if (arr[j] > arr[j + 1]) {            var temp = arr[j + 1];
            arr[j + 1] = arr[j];
            arr[j] = temp;
        }
    }
  }  return arr;
}

function selectionSort(arr) {  var len = arr.length;  var minIndex, temp;   // 寻找最小的数，将索引保存
  for (var i = 0; i < len - 1; i++) {
    minIndex = i;    for (var j = i + 1; j < len; j++) {        if (arr[j] < arr[minIndex]) {
            minIndex = j;
        }
    }
    temp = arr[i];
    arr[i] = arr[minIndex];
    arr[minIndex] = temp;
  }  return arr;
}

function 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) {
        arr[preIndex + 1] = arr[preIndex];
        preIndex--;
    }
    arr[preIndex + 1] = current;
  }  return arr;
}

function shellSort(arr) {  var len = arr.length, temp, gap = 1;  //动态定义间隔序列
  while (gap < len / 3) {
    gap = gap * 3 + 1;
  }  for (gap; gap > 0; gap = Math.floor(gap / 3)) {    for (var i = gap; i < len; i++) {
        temp = arr[i];        for (var j = i - gap; j >= 0 && arr[j] > temp; j -= gap) {
            arr[j + gap] = arr[j];
        }
        arr[j + gap] = temp;
    }
  }  return arr;
}

function mergeSort(arr) {  var len = arr.length;  if (len < 2) {    return arr;
  }  var middle = Math.floor(len / 2),
    left = arr.slice(0, middle),
    right = arr.slice(middle);  return merge(mergeSort(left), mergeSort(right));  function merge(left, right) {    var result = [];    while (left.length && right.length) {        if (left[0] <= right[0]) {
            result.push(left.shift());
        } else {
            result.push(right.shift());
        }
    }    while (left.length)
        result.push(left.shift());    while (right.length)
        result.push(right.shift());    return result;
  }
}