JavaScript數據結構與算法之二叉樹添加/刪除節點操作示例

function Node(data,left,right) {
 this.data = data;
 this.left = left;
 this.right = right;
 this.show = show;
}
function show() {
 return this.data;
}
function BST() {
 this.root = null;
 this.insert = insert;
 this.inOrder = inOrder;
 this.getMin = getMin;
 this.getMax = getMax;
 this.find = find;
 this.remove = remove;
}
function insert(data) {
 var n = new Node(data,null,null);
 if(this.root == null) {
 this.root = n;
 }else {
 var current = this.root;
 var parent;
 while(current) {
 parent = current;
 if(data < current.data) {
 current = current.left;
 if(current == null) {
 parent.left = n;
 break;
 }
 }else {
 current = current.right;
 if(current == null) {
 parent.right = n;
 break;
 }
 }
 }
 }
}
// 中序遍歷
function inOrder(node) {
 if(!(node == null)) {
 inOrder(node.left);
 console.log(node.show());
 inOrder(node.right);
 }
}
// 先序遍歷 
function preOrder(node) {
 if(!(node == null)) {
 console.log(node.show());
 preOrder(node.left);
 preOrder(node.right);
 }
}
// 后序遍歷
function postOrder(node) {
 if(!(node == null)) {
 postOrder(node.left);
 postOrder(node.right);
 console.log("后序遍歷"+node.show());
 }
}
// 二叉樹查找最小值
function getMin(){
 var current = this.root;
 while(!(current.left == null)) {
 current = current.left;
 }
 return current.data;
}
// 二叉樹上查找最大值
function getMax() {
 var current = this.root;
 while(!(current.right == null)) {
 current = current.right;
 }
 return current.data;
}
// 查找給定值
function find(data) {
 var current = this.root;
 while(current != null) {
 if(current.data == data) {
 return current;
 }else if(data < current.data) {
 current = current.left;
 }else {
 current = current.right;
 }
 }
 return null;
}
function remove(data) {
 root = removeNode(this.root,data);
}
function getSmallest(node) {
 if (node.left == null) {
 return node;
 }
 else {
 return getSmallest(node.left);
 }
}
function removeNode(node,data) {
 if(node == null) {
 return null;
 }
 if(data == node.data) {
 // 沒有子節點的節點
 if(node.left == null && node.right == null) {
 return null;
 } 
 // 沒有左子節點的節點
 if(node.left == null) {
 return node.right;
 }
 // 沒有右子節點的節點
 if(node.right == null) {
 return node.left;
 }
 // 有2個子節點的節點
 var tempNode = getSmallest(node.right);
 node.data = tempNode.data;
 node.right = removeNode(node.right,tempNode.data);
 return node;
 }else if(data < node.data) {
 node.left = removeNode(node.left,data);
 return node;
 }else {
 node.right = removeNode(node.right,data);
 return node;
 }
}
//代碼初始化如下：
var nums = new BST();
nums.insert(23);
nums.insert(45);
nums.insert(16);
nums.insert(37);
nums.insert(3);
nums.insert(99);
nums.insert(22);
var min = nums.getMin();
console.log(min);
var max = nums.getMax();
console.log(max);
var value = nums.find("45");
console.log(value);
nums.remove(23);