Javascript 为了在广度优先搜索算法中打印水平，我应该做什么。

为了在二叉树中按级别打印值，可以在下面的算法中执行什么操作

BinarySearchTree.prototype.breadthFirstTraversal = function() {
    console.log("Breadth First Traversal");

    var q = []
    q.push(this.root);//You don't need to write the root here, it will be written in the loop
    while (q.length > 0)
    {
        var n = q.shift();
        console.log(n.value); //Only write the value when you dequeue it
        if (n.left !=null)
        {
            q.push(n.left);//enqueue the left child
        }
        if (n.right !=null)
        {
            q.push(n.right);//enque the right child
        }
    }
};

---

存储每个节点的级别，并仅在级别更改时打印它们：

BinarySearchTree.prototype.breadthFirstTraversal = function() {
    console.log("Breadth First Traversal");

    var q = [];
    var prevLevel = -1; // monitor level switch
    var byLevel = []; // store node values for printing
    this.root.level = 0; // set root level
    q.push(this.root);//You don't need to write the root here, it will be written in the loop
    byLevel.push(this.root.value);
    while (q.length > 0)
    {
        var n = q.shift();
        // Next level, print and reset
        if (n.level > prevLevel) {
            console.log(byLevel);
            byLevel = [];
            prevLevel = n.level;
        }
        if (n.left !=null)
        {
            n.left.level = n.level + 1;
            q.push(n.left);//enqueue the left child
            byLevel.push(n.left.value);
        }
        if (n.right !=null)
        {
            n.right.level = n.level + 1;
            q.push(n.right);//enque the right child
            byLevel.push(n.right.value);
        }
    }

    if (byLevel.length > 0) {
        console.log(byLevel);
    }
};

---

存储每个节点的级别，并仅在级别更改时打印它们：

BinarySearchTree.prototype.breadthFirstTraversal = function() {
    console.log("Breadth First Traversal");

    var q = [];
    var prevLevel = -1; // monitor level switch
    var byLevel = []; // store node values for printing
    this.root.level = 0; // set root level
    q.push(this.root);//You don't need to write the root here, it will be written in the loop
    byLevel.push(this.root.value);
    while (q.length > 0)
    {
        var n = q.shift();
        // Next level, print and reset
        if (n.level > prevLevel) {
            console.log(byLevel);
            byLevel = [];
            prevLevel = n.level;
        }
        if (n.left !=null)
        {
            n.left.level = n.level + 1;
            q.push(n.left);//enqueue the left child
            byLevel.push(n.left.value);
        }
        if (n.right !=null)
        {
            n.right.level = n.level + 1;
            q.push(n.right);//enque the right child
            byLevel.push(n.right.value);
        }
    }

    if (byLevel.length > 0) {
        console.log(byLevel);
    }
};

---

只是想添加它，因为它不需要像上面的解决方案那样存储每个对应节点的级别，所以不需要向对象添加属性。如果你仔细想想，这个队列最多有两个不同的级别。因此，您只需要一个全局标记就可以知道您是否正在处理一个新级别，还需要一个标志来知道您是否应该标记正在推送的新右或左节点

BinarySearchTree.prototype.breadthFirstTraversal = function() {
        console.log("Breadth First Traversal");

var q = new Array();
q.push(this.root);

var printArray = [];
var printArray.push(this.root.value);

var newlevel = false;
var marker = 1;
var level = 0;


while(q.length > 0){


    if(marker==1){
        console.log("level: " + level);
        console.log(printArray);
        newlevel = true;
    }

     var n = q.shift();
     printArray.shift();

     marker -= 1;
     //console.log(n.value);

    if(n.left != null){
        q.push(n.left);
        printArray.push(n.left.value);

        if(newlevel){
            marker = q.length;
            level+=1;
            newlevel = false;
        }
    }

    if(n.right != null){
        q.push(n.right);
        printArray.push(n.right.value);

        if(newlevel){
            marker = q.length;
            level+=1;    
            newlevel = false;
        }
    }

}
};

---

只是想添加它，因为它不需要像上面的解决方案那样存储每个对应节点的级别，所以不需要向对象添加属性。如果你仔细想想，这个队列最多有两个不同的级别。因此，您只需要一个全局标记就可以知道您是否正在处理一个新级别，还需要一个标志来知道您是否应该标记正在推送的新右或左节点

BinarySearchTree.prototype.breadthFirstTraversal = function() {
        console.log("Breadth First Traversal");

var q = new Array();
q.push(this.root);

var printArray = [];
var printArray.push(this.root.value);

var newlevel = false;
var marker = 1;
var level = 0;


while(q.length > 0){


    if(marker==1){
        console.log("level: " + level);
        console.log(printArray);
        newlevel = true;
    }

     var n = q.shift();
     printArray.shift();

     marker -= 1;
     //console.log(n.value);

    if(n.left != null){
        q.push(n.left);
        printArray.push(n.left.value);

        if(newlevel){
            marker = q.length;
            level+=1;
            newlevel = false;
        }
    }

    if(n.right != null){
        q.push(n.right);
        printArray.push(n.right.value);

        if(newlevel){
            marker = q.length;
            level+=1;    
            newlevel = false;
        }
    }

}
};