[数据结构与算法]【LeetCode 100】相同的树

深度优先搜索

	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;
    	return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
    }

广度优先搜索

	public boolean isSameTree1(TreeNode p, TreeNode q) {
    	if (p == null && q == null) {
            return true;
        } else if (p == null || q == null) {
            return false;
        }
    	
    	Queue<TreeNode> q1 = new LinkedList<TreeNode>();
    	Queue<TreeNode> q2 = new LinkedList<TreeNode>();
    	q1.offer(p);
    	q2.offer(q);
    	while (!q1.isEmpty() && !q2.isEmpty())
    	{
    		TreeNode n1 = q1.poll();
    		TreeNode n2 = q2.poll(); 
    		if (n1 == null && n2 == null)
    			continue;
    		if (n1 == null ^ n2 == null) {
                return false;
            }
    		if (n1.val != n2.val)
    			return false;
    		q1.offer(n1.left);
    		q1.offer(n1.right);
    		q2.offer(n2.left);
    		q2.offer(n2.right);
    	}
    	return true;
    }