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public class ListOfDepth {
public static class TreeNode {
int val;
TreeNode left;
TreeNode right;
TreeNode(int x) {
val = x;
}
}
public static class ListNode {
int val;
ListNode next;
ListNode(int x) {
val = x;
}
}
public ListNode[] listOfDepth(TreeNode tree) {
//递归计算出树的深度
int depth = getDepth(tree);
//初始化保存路径数组
ListNode[] listNodes = new ListNode[depth];
//采用队列临时存放树上每一层的节点
Queue<TreeNode> queue = new LinkedList<>();
queue.offer(tree);
int index = 0;
//循环终止条件：树的最大深度
while (!queue.isEmpty()) {
int size = queue.size();
ListNode newhead = new ListNode(0);
ListNode indexNode = newhead;
for (int i = 0; i < size; i++) {
TreeNode poll = queue.poll();
indexNode.next = new ListNode(poll.val);
indexNode = indexNode.next;
if (poll.left != null) {
queue.offer(poll.left);
}
if (poll.right != null) {
queue.offer(poll.right);
}
}
listNodes[index++] = newhead.next;
}
return listNodes;
}
private int getDepth(TreeNode treeNode) {
if (treeNode == null) {
return 0;
}
return Math.max(getDepth(treeNode.left), getDepth(treeNode.right)) + 1;
}
}
