leetcode--Same Tree

Given two binary trees, write a function to check if they are equal or not.

Two binary trees are considered equal if they are structurally identical and the nodes have the same value.

/**
 * 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) {
        boolean isSame = true;
		if((p != null && q == null) || (p == null && q != null) ||
			(p != null && q != null && p.val != q.val))
			 isSame = false;
		else if (p == null && q == null)
			isSame = true;
		else{
			isSame = isSameTree(p.left, q.left) & (isSameTree(p.right, q.right));
		}
		return isSame;    
    }
}