Same Tree

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     public int val;
 *     public TreeNode left;
 *     public TreeNode right;
 *     public TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public bool IsSameTree(TreeNode p, TreeNode q) {
        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;
        }
        
    }
}