Same Tree

simple recursion problem

/**
 * 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) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        if(p == null && q == null)
            return true;
        if(p == null && q != null)
            return false;
        if(p!=null && q == null)
            return false;
        if(p.val == q.val)
            return (isSameTree(p.left, q.left))&&(isSameTree(p.right,q.right));
        else
            return false;
        
    }
}