LeetCode——100. 相同的树

1.问题描述

2.解决办法

广度优先遍历

• 创建两个队列，将两个根节点分别放入队列中
• 进行出队，并将两者各自的左右结点放入队列
• 比较出队的结点的值是否相同，不相同直接返回false

3.代码实现

class Solution {
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if (p == null && q == null) {
            return true;
        } else if (p == null || q == null) {
            return false;
        }
        Queue<TreeNode> queue1 = new LinkedList<TreeNode>();
        Queue<TreeNode> queue2 = new LinkedList<TreeNode>();
        queue1.offer(p);
        queue2.offer(q);
        while (!queue1.isEmpty() && !queue2.isEmpty()) {
            TreeNode node1 = queue1.poll();
            TreeNode node2 = queue2.poll();
            if (node1.val != node2.val) {
                return false;
            }
            TreeNode left1 = node1.left, right1 = node1.right, left2 = node2.left, right2 = node2.right;
            if (left1 == null ^ left2 == null) {
                return false;
            }
            if (right1 == null ^ right2 == null) {
                return false;
            }
            if (left1 != null) {
                queue1.offer(left1);
            }
            if (right1 != null) {
                queue1.offer(right1);
            }
            if (left2 != null) {
                queue2.offer(left2);
            }
            if (right2 != null) {
                queue2.offer(right2);
            }
        }
        return queue1.isEmpty() && queue2.isEmpty();
    }
}

作者：LeetCode-Solution
链接：https://leetcode-cn.com/problems/same-tree/solution/xiang-tong-de-shu-by-leetcode-solution/
来源：力扣（LeetCode）
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