三大经典算法之冒泡排序、插入排序和快速排序

引言

好久不写文章了，最近在学小程序感觉没得写，今天就来说说面试必备的排序算法吧，话不多唠，直接上代码，以下会画图讲解每种排序的规则

冒泡排序

代码见图一，注解见图二（以下同上）

 function bubbleSort(ary) {
     for (let i = 0; i < ary.length-1; i++) {
       for (let j = 0; j < ary.length - 1 - i; j++) {
         if (ary[j] > ary[j + 1]) {
           let temp = ary [j + 1];
           ary [j + 1] = ary[j];
           ary[j] = temp;
         }
       }
     }
     return ary
   }

   let ary = [12, 8, 24, 16, 1];
   let newAry = bubbleSort(ary);
   console.log(newAry);

插入排序

function insertSort(ary) {
     let handle = [];
     handle.push(ary[0]);
     for (let i = 1; i < ary.length; i++) {
       for (let j = handle.length - 1; j >= 0; j--) {
         if (ary[i] > handle[j]) {
           handle.splice(j + 1, 0, ary[i]);
           break
         }
         if (j === 0) {
           handle.unshift(ary[i])
         }
       }
     }
     return handle
   }
   let ary = [12, 8, 24, 16, 1];
   let newAry = insertSort(ary);
   console.log(newAry);

快速排序

 function quickSort(ary) {
    if (ary.length <= 1) return ary;
    let middle = ary.splice(Math.floor(ary.length / 2), 1)[0];
    let leftAry = [], rightAry = [];
    ary.forEach(v => v < middle ? leftAry.push(v) : rightAry.push(v));
    return quickSort(leftAry).concat(middle, quickSort(rightAry))
  }
  let ary = [12, 8, 15, 10, 24, 16, 1];
  let newAry = quickSort(ary);
  console.log(newAry);

今天不想说话（其实并不知道说啥），就这样，哈哈哈哈哈