题解 | #对称的二叉树#

/*
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    boolean isSymmetrical(TreeNode root) {
        if(root == null) return true;
        return isSame(root.left,root.right);
    }
    
    boolean isSame(TreeNode p,TreeNode q){
        if(p == null && q != null) return false;
        if(p != null && q == null) return false;
        if(p == null && q == null) return true;
        if(p.val != q.val) return false;
        return isSame(p.left,q.right) && isSame(p.right,q.left);
    }
}