Checking Symmetric Tree
Symmetric Tree:
Each node's left and right children can be swapped without changing the tree's look.
Symmetry Analysis:
We dive into recursive logic with isMirror, comparing subtrees to check symmetry by comparing node values and their children.
Symmetry Check:
Using isSymmetric, we oversee the whole tree's symmetry by calling isMirror on left and right subtrees.
1class Node {
2 constructor(val) {
3 this.val = val;
4 this.left = null;
5 this.right = null;
6 }
7 }
8
9
10 const one = new Node(1);
11 const two = new Node(2);
12 const three = new Node(3);
13 const threeRight = new Node(3);
14 const twoRight = new Node(2);
15 const four = new Node(4);
16 const fourRight = new Node(4);
17 const five = new Node(5);
18 const six = new Node(6);
19 const seven = new Node(7);
20 const eight = new Node(8);
21
22
23// one.left = two;
24// one.right = three;
25// two.right = five;
26// two.left = four;
27// five.right = seven;
28// five.left = six;
29// seven.left = eight;
30
31
32 one.left = two;
33 one.right = twoRight;
34 two.right = four;
35 two.left = three;
36 twoRight.right = threeRight;
37 twoRight.left = fourRight;
38
39 function isMirror(node1, node2) {
40 if(!node1 && !node2) return true;
41 if(!node1 || !node2) return false;
42 if(node1.val !== node2.val) return false;
43
44 return isMirror(node1.left, node2.right) && isMirror(node1.right, node2.left)
45 }
46 var isSymmetric = function(root) {
47 if(!root) return true;
48 return isMirror(root.left, root.right)
49 };
50
51
52console.log(isSymmetric(one))
53