day48（12.29）——leetcode面试经典150

117. 填充每个节点的下一个右侧节点指针 II

117. 填充每个节点的下一个右侧节点指针 Ⅱ

bfs直接秒了

题目：

题解：

/* // Definition for a Node. class Node { public int val; public Node left; public Node right; public Node next; public Node() {} public Node(int _val) { val = _val; } public Node(int _val, Node _left, Node _right, Node _next) { val = _val; left = _left; right = _right; next = _next; } }; */ class Solution { public Node connect(Node root) { if(root == null) { return null; } Queue<Node> queue = new LinkedList<>(); queue.offer(root); while(queue.size()>0) { int size = queue.size(); for(int i=0;i<size;i++) { Node node = queue.poll(); if(i<size-1) { node.next = queue.peek(); } if(node.left != null) { queue.offer(node.left); } if(node.right != null) { queue.offer(node.right); } } } return root; } }