前端算法之二叉树遍历（深序中序后序广序）

function Node(value) {
    this.value = value;
    this.left = null;
    this.right = null;
}

let a = new Node("a");
let b = a.left = new Node("b");
let c = a.right = new Node("c");
let d = b.left = new Node("d");
let e = b.right = new Node("e");
let f = c.left = new Node("f");
let g = c.right = new Node("g");

function fn1(node) {
    if (!node) return
    console.log(node.value)
    fn1(node.left)
    fn1(node.right)
}

function fn2(node) {
    if (!node) return
    fn2(node.left)
    console.log(node.value)
    fn2(node.right)
}

function fn3(node) {
    if (!node) return
    fn3(node.left)
    fn3(node.right)
    console.log(node.value)
}

function bfs(node) {
    let queue = [node]
    while (queue.length) {
        let first = queue.shift()
        if (!first) return
        console.log(first.value)
        queue.push(first.left)
        queue.push(first.right)
    }
}

bfs(a)