CS-Notes/notes/32.2 把二叉树打印成多行.md
2019-11-02 17:33:10 +08:00

40 lines
1.1 KiB
Java

# 32.2 把二叉树打印成多行
[NowCoder](https://www.nowcoder.com/practice/445c44d982d04483b04a54f298796288?tpId=13&tqId=11213&tPage=1&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking&from=cyc_github)
## 题目描述
和上题几乎一样
## 解题思路
```java
ArrayList<ArrayList<Integer>> Print(TreeNode pRoot) {
ArrayList<ArrayList<Integer>> ret = new ArrayList<>();
Queue<TreeNode> queue = new LinkedList<>();
queue.add(pRoot);
while (!queue.isEmpty()) {
ArrayList<Integer> list = new ArrayList<>();
int cnt = queue.size();
while (cnt-- > 0) {
TreeNode node = queue.poll();
if (node == null)
continue;
list.add(node.val);
queue.add(node.left);
queue.add(node.right);
}
if (list.size() != 0)
ret.add(list);
}
return ret;
}
```
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