各种排序算法2

// 冒泡排序(BubbleSort) O(n2)
const BubbleSort  = (arr = []) => {
  const startTime = new Date().getTime();
  if (!Array.isArray(arr)) return false;
  const tmpArr = arr.slice(0);
  let changeFlag = false;
  for (let i=0; i<tmpArr.length-1; i++) {
    for(let j=tmpArr.length-1;j>0;j--) {
      if (tmpArr[j-1]>tmpArr[j]) {
        [tmpArr[j-1],tmpArr[j]]=[tmpArr[j],tmpArr[j-1]];
        changeFlag = true;
      }
    }
    if (!changeFlag) break; // 优化排序实现
  }
  const endTime = new Date().getTime();
  return [tmpArr, endTime-startTime];
}

// 改进冒泡排序(BubbleSort) O(n2/2)
const BubbleSort2  = (arr = []) => {
  const startTime = new Date().getTime();
  if (!Array.isArray(arr)) return false;
  const tmpArr = arr.slice(0);
  let changeFlag = false;
  for (let i=0; i<tmpArr.length-1; i++) {
    for(let j=tmpArr.length-1;j>i;j--) {
      if (tmpArr[j-1]>tmpArr[j]) {
        [tmpArr[j-1],tmpArr[j]]=[tmpArr[j],tmpArr[j-1]];
        changeFlag = true;
      }
    }
    if (!changeFlag) break; // 优化排序实现
  }
  const endTime = new Date().getTime();
  return [tmpArr, endTime-startTime];
}

// 选择排序(SelctionSort)
// 普通实现
const SelctionSort = (arr = []) => {
  const startTime = new Date().getTime();
  if (!Array.isArray(arr)) return false;
  const tmpArr = arr.slice(0);
  for (let i=0; i<tmpArr.length; i++) {
    let minIndex = i;
    for(let j=i+1;j<tmpArr.length;j++) {
      if (tmpArr[minIndex]>tmpArr[j]) {
        minIndex = j;
      }
    }
    if (minIndex !==i) {
      [tmpArr[i],tmpArr[minIndex]]=[tmpArr[minIndex], tmpArr[i]];
    }
  }
  const endTime = new Date().getTime();
  return [tmpArr, endTime-startTime];
}

// 优化选择排序
const SelctionSort2 = (arr=[]) => {
  const startTime = new Date().getTime();
  if (!Array.isArray(arr)) return false;
  const tmpArr = arr.slice(0);
  const len = tmpArr.length;
  //最小值下标
    let minIndex = 0;
    //最大值下标
    let maxIndex = 0;
    let left = 0;
    let right = len - 1;
    let j = 0;
  while (left<right) {
    maxIndex = left;
    minIndex = left;
    for (j = left; j <= right; j++) {
      if (tmpArr[j]>tmpArr[maxIndex]) {
        maxIndex = j;
      }
      if (tmpArr[j] < tmpArr[minIndex])    {
        minIndex = j;
      }
    }
    //将最大值插到最后
    if (maxIndex != right) {
      [tmpArr[maxIndex],tmpArr[right]]=[tmpArr[right],tmpArr[maxIndex]];
      // swap(tmpArr[maxIndex], tmpArr[right]);
    }
    //防止minpos在最大值要插入的位置
    if (minIndex == right) {
      minIndex = maxIndex;
    }
    //将最小值插到最前面
    if (minIndex != left) {
      [tmpArr[left],tmpArr[minIndex]]=[tmpArr[minIndex],tmpArr[left]];
      // swap(tmpArr[minIndex], tmpArr[left]);
    }
    left++;
    right--;
  }
  const endTime = new Date().getTime();
  return [endTime-startTime];
}

//  插入排序(Insertion Sort)
const InsertionSort = (arr=[]) => {
  const startTime = new Date().getTime();
  if (!Array.isArray(arr)) return false;
  const tmpArr = arr.slice(0);
  for (let i=0; i<tmpArr.length; i++) {
    for (let j=i+1;j>0;j--) {
      if (tmpArr[j-1]>tmpArr[j]) {
        [tmpArr[j-1],tmpArr[j]]=[tmpArr[j],tmpArr[j-1]];
      } else {
        break; // 优化插入排序
      }
    }
  }
  const endTime = new Date().getTime();
  return [tmpArr, endTime-startTime];
}

// 快速排序(Quicksort)
const Quicksort = (arr=[]) => {
  const startTime = new Date().getTime();
  if (!Array.isArray(arr)) return false;
  const tmpArr = arr.slice(0);
  let result;
  const quickSort_ = (arr=[]) => {
　　if (arr.length <= 1) { return arr; }
    const pivotIndex = Math.floor(arr.length/2);
    const pivot = arr.splice(pivotIndex, 1);
    const left = [];
    const right = [];
    const center = [];
    for (let i = 0; i < arr.length; i++){
　　　if (arr[i] < pivot[0]) {
　　　　　left.push(arr[i]);
　　　} else if (arr[i] === pivot[0]) {
        center.push(arr[i]);
      } else {
　　　　　right.push(arr[i]);
　　　}
　　}
　　return quickSort_(left).concat([...pivot,...center], quickSort_(right));
  };
  result = quickSort_(tmpArr);
  const endTime = new Date().getTime();
  return [result, endTime-startTime];
}

// 快速排序优化 (Quicksort) 原地快排
const Quicksort2 = (arr=[]) => {
  const startTime = new Date().getTime();
  if (!Array.isArray(arr)) return false;
  const tmpArr = arr.slice(0);
  let result;
  const Partition = (arr,start,end) => {
    let j = start,
    v = arr[j]; // 哨兵
    for (let i = start+1; i <= end; i++) {
      if(arr[i] < v){
        [arr[j + 1], arr[i]] = [arr[i], arr[j + 1]];
        j++;
      }
      // if(i==Math.floor((end-start)/2)){
      //   [arr[start], arr[j]] = [arr[j], arr[start]];
      //   return Math.floor((end-start)/2);
      // }
    }
    [arr[start], arr[j]] = [arr[j], arr[start]];
    if (j==start) return Math.ceil((end-start)/2);
    return j;  //返回基准元素位置
  }
  const quickSort2_ = (arr,start,end) => {
    if (start < end) {
      const mid = Partition(arr,start,end); //返回基准元素位置
      quickSort2_(arr,start,mid-1);   //左边快速排序
      quickSort2_(arr,mid+1,end);  //右边快速排序
    }
    return arr;
  }
  result = quickSort2_(tmpArr,0,tmpArr.length-1);
  const endTime = new Date().getTime();
  return [result, endTime-startTime];
}


// 三路快排
const Quicksort3 = (arr=[]) => {
  const startTime = new Date().getTime();
  if (!Array.isArray(arr)) return false;
  const tmpArr = arr.slice(0);
  const qsort = arr => arr.length <=1 ? arr : qsort(arr.filter(x => x < arr[0])).concat(arr.filter(x => x==arr[0])).concat(qsort(arr.filter(x => x > arr[0])));
  qsort(tmpArr);
  const endTime = new Date().getTime();
  return [tmpArr, endTime-startTime];
}
// 数组自带排序
const SelfSort = (arr=[]) => {
  const startTime = new Date().getTime();
  if (!Array.isArray(arr)) return false;
  const tmpArr = arr.slice(0);
  tmpArr.sort((a,b)=>a-b);
  const endTime = new Date().getTime();
  return [tmpArr, endTime-startTime];
}

// 二分查找
const Binary_search = (arr, key) => {
  let low=0,
  high=arr.length-1;
  while(low<=high){
    const mid=parseInt((high+low)/2);
    if(key==arr[mid]){
      return mid;
    }else if(key>arr[mid]){
      low=mid+1;
    }else if(key<arr[mid]){
      high=mid-1;
    }else{
      return -1;
    }
  }
}

测试代码

let size = 5;
const arr = new Array(size).fill('').map(() => size/20);
// console.log(BubbleSort(arr)[1]);
// console.log(InsertionSort(arr)[1]);
// console.log(SelctionSort2(arr)[1]);
// console.log(SelctionSort(arr)[1]);
console.log(Quicksort(arr)[1]);
// console.log(arr.join(','));
// console.log(Quicksort2(arr)[1]);
console.log(Quicksort3(arr)[1]);
// console.log(arr.join(','));
// console.log(SelfSort(arr)[1]);
// console.log(arr.join(','));
console.log(Quicksort2([5,9,12,5,36,12,35,65,98,65,3,11,60,19,87,29,3,19,30])[0]);
// console.log(Quicksort([5,9,12,5,36,12,35,65,98,65,3,11,60,19,87,29,3,19,30])[0]);
// console.log(SelfSort([5,9,12,5,36,12,35,65,98,65,3,11,60,19,87,29,3,19,30])[0]);