LeetCode Same Tree

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if (p==null && q==null) {
            return true;
        }
        if (p==null || q==null) {
            return false;
        }
        if (p.val!=q.val) {
            return false;
        }else {
            if (isSameTree(p.left, q.left)&&isSameTree(p.right, q.right)) {
                return true;
            }else {
                return false;
            }
        }
    }
}