三大经典排序算法

冒泡排序

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

插入排序

function InsertSort(arr) {
    let newArr = []
    newArr.push(arr[0])
    for (let i = 1; i < arr.length; i++) {
        for(let j = newArr.length - 1; j >= 0; j--){
            if (arr[i] > newArr[j]) {
                newArr.splice(j + 1,0,arr[i])
                break
            }
            if (j === 0) {
                newArr.unshift(arr[i])
            }
        }
        
    }
    return newArr
}

快速排序

function QuickSort(arr) {
    if (arr.length <= 1) {
        return arr
    }
    var pointIndex = Math.floor(arr.length / 2)
    var pointValue = arr.splice(pointIndex, 1)[0]
    var leftArr = []
    var rightArr = []
    for(var i = 0; i <arr.length; i++){
        var cur = arr[i]
        cur > pointValue ? rightArr.push(cur) : leftArr.push(cur);
    }
    return QuickSort(leftArr).concat(pointValue, QuickSort(rightArr))
}