排序算法

冒泡排序:

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

const arr = [5, 1, 6, 3]
arr.bubbleSort()
console.log(arr)

快速排序

Array.prototype.fastSort = function () {
    const sort = (arr) => {
        if (arr.length < 2) {
            return arr
        }
        let left = []
        let right = []
        let mid = arr[0]
        for (let i = 1; i < arr.length; i++) {
            if (arr[i] > mid) {
                right.push(arr[i])
            } else {
                left.push(arr[i])
            }
        }
        return [...sort(left), mid, ...sort(right)]
    }
    let newArr = sort(this)
    for (let i = 0; i < this.length; i++) {
        this[i] = newArr[i]
    }
}
let arr = [4, 1, 2, 6, 8, 7, 3, 10, 9]
arr.fastSort()
console.log(arr)

选择排序

Array.prototype.selectSort = function () {
    for (let i = 0; i < this.length - 1; i++) {
        let indexMin = i;
        for (let j = i; j < this.length; j++) {
            if (this[j] < this[indexMin]) {
                indexMin = j
            }
        }
        if (indexMin !== i) {
            let temp = this[i]
            this[i] = this[indexMin]
            this[indexMin] = temp
        }

    }
}
const arr = [5, 1, 6, 3]
arr.selectSort()
console.log(arr)

插入排序

Array.prototype.insertSort=function(){
    for(let i=0;i<this.length;i++){
        let temp=this[i]
        let j=i
        while(j>0){
            if(this[j-1]>temp){
                this[j]=this[j-1]
            }
            else{
                break;
            }
            j--
        }
        this[j]=temp
    }
}
const arr = [5, 1, 6, 3]
arr.insertSort()
console.log(arr)

图的深度优先遍历

const visited = new Set()
const dfs = (n) => {
    console.log(n)
    visited.add(n)
    graph[n].forEach(c => {
        if (!visited.has(c)) {
            dfs(c)
        }
    })
}
dfs(2)