Same Binary 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) {
        // Note: The Solution object is instantiated only once and is reused by each test case.
        /* BFS */
        if(p==null&&q==null) return true;   //check the leaf nodes
        if(p==null||q==null) return false;
        if(p.val!=q.val) return false;
        boolean left=isSameTree(p.left,q.left);
        if(!left) return left;
        boolean right=isSameTree(p.right,q.right);
        return right;
    }
}