0101.对称二叉树JavaScript版本

This commit is contained in:
xll
2021-05-24 14:59:11 +08:00
parent ff3605a52b
commit b20ac9cbc3

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@ -379,6 +379,90 @@ const check = (leftPtr, rightPtr) => {
return leftPtr.val === rightPtr.val && check(leftPtr.left, rightPtr.right) && check(leftPtr.right, rightPtr.left)
}
```
JavaScript:
递归判断是否为对称二叉树:
```javascript
var isSymmetric = function(root) {
//使用递归遍历左右子树 递归三部曲
// 1. 确定递归的参数 root.left root.right和返回值true false
const compareNode=function(left,right){
//2. 确定终止条件 空的情况
if(left===null&&right!==null||left!==null&&right===null){
return false;
}else if(left===null&&right===null){
return true;
}else if(left.val!==right.val){
return false;
}
//3. 确定单层递归逻辑
let outSide=compareNode(left.left,right.right);
let inSide=compareNode(left.right,right.left);
return outSide&&inSide;
}
if(root===null){
return true;
}
return compareNode(root.left,root.right);
};
```
队列实现迭代判断是否为对称二叉树:
```javascript
var isSymmetric = function(root) {
//迭代方法判断是否是对称二叉树
//首先判断root是否为空
if(root===null){
return true;
}
let queue=[];
queue.push(root.left);
queue.push(root.right);
while(queue.length){
let leftNode=queue.shift();//左节点
let rightNode=queue.shift();//右节点
if(leftNode===null&&rightNode===null){
continue;
}
if(leftNode===null||rightNode===null||leftNode.val!==rightNode.val){
return false;
}
queue.push(leftNode.left);//左节点左孩子入队
queue.push(rightNode.right);//右节点右孩子入队
queue.push(leftNode.right);//左节点右孩子入队
queue.push(rightNode.left);//右节点左孩子入队
}
return true;
};
```
栈实现迭代判断是否为对称二叉树:
```javascript
var isSymmetric = function(root) {
//迭代方法判断是否是对称二叉树
//首先判断root是否为空
if(root===null){
return true;
}
let stack=[];
stack.push(root.left);
stack.push(root.right);
while(stack.length){
let rightNode=stack.pop();//左节点
let leftNode=stack.pop();//右节点
if(leftNode===null&&rightNode===null){
continue;
}
if(leftNode===null||rightNode===null||leftNode.val!==rightNode.val){
return false;
}
stack.push(leftNode.left);//左节点左孩子入队
stack.push(rightNode.right);//右节点右孩子入队
stack.push(leftNode.right);//左节点右孩子入队
stack.push(rightNode.left);//右节点左孩子入队
}
return true;
};
```
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