116. 填充每个节点的下一个右侧节点指针
问题116 填充每个节点的下一个右侧节点指针 ★★☆☆☆
https://leetcode-cn.com/problems/populating-next-right-pointers-in-each-node/
这个题目其实就是二叉树层序遍历的变种,就是每一层从左到右维护成一个链表嘛,在层序遍历的基础上稍做修改即可。
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public Node connect(Node root) {
if (root == null) {
return null;
}
Queue<Node> queue = new LinkedList<>();
queue.add(root);
Node dummy = new Node(-1);
while (!queue.isEmpty()) {
int size = queue.size();
Node last = dummy;
for (int i = 0; i < size; i++) {
Node cur = queue.poll();
last.next = cur;
last = cur;
if (cur.left != null) {
queue.offer(cur.left);
}
if (cur.right != null) {
queue.offer(cur.right);
}
}
}
return root;
}
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