Leetcode/SymmetricTree.java at main · mervesaltik/Leetcode · GitHub

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/* Example 1 : Your input : root = [1,2,2,3,4,4,3]  Output : true
 * Example 2 : Your input : root = [1,2,2,null,3,null,3]  Output : false
 */


/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */

class SymmetricTree {
    public boolean isSymmetric(TreeNode root) {
        if(root == null){
            return true;
        }
        return isSymmetric(root.left,root.right);

    }

    public boolean isSymmetric(TreeNode left , TreeNode right){
        if(left == null || right == null){
            return left == right;
        }

        if(left.val != right.val){
            return false;
        }

        return isSymmetric(left.left,right.right) && isSymmetric(left.right,right.left);
    }


}