100 lines
2.3 KiB
Java
100 lines
2.3 KiB
Java
//给定一个 N 叉树，返回其节点值的层序遍历。（即从左到右，逐层遍历）。
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//
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// 树的序列化输入是用层序遍历，每组子节点都由 null 值分隔（参见示例）。
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//
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//
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//
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// 示例 1：
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//
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//
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//
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//
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//输入：root = [1,null,3,2,4,null,5,6]
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//输出：[[1],[3,2,4],[5,6]]
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//
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//
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// 示例 2：
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//
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//
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//
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//
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//输入：root = [1,null,2,3,4,5,null,null,6,7,null,8,null,9,10,null,null,11,null,12,
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//null,13,null,null,14]
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//输出：[[1],[2,3,4,5],[6,7,8,9,10],[11,12,13],[14]]
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//
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//
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//
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//
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// 提示：
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//
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//
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// 树的高度不会超过 1000
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// 树的节点总数在 [0, 10^4] 之间
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//
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// Related Topics 树 广度优先搜索
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// 👍 170 👎 0
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package leetcode.editor.cn;
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import com.code.leet.entiy.Node;
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import java.util.ArrayList;
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import java.util.LinkedList;
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import java.util.List;
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import java.util.Queue;
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//429:N 叉树的层序遍历
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class NAryTreeLevelOrderTraversal {
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public static void main(String[] args) {
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//测试代码
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Solution solution = new NAryTreeLevelOrderTraversal().new Solution();
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}
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//力扣代码
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//leetcode submit region begin(Prohibit modification and deletion)
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/*
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// Definition for a Node.
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class Node {
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public int val;
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public List<Node> children;
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public Node() {}
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public Node(int _val) {
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val = _val;
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}
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public Node(int _val, List<Node> _children) {
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val = _val;
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children = _children;
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}
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};
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*/
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class Solution {
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public List<List<Integer>> levelOrder(Node root) {
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if (root == null) {
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return new ArrayList<>();
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}
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Queue<Node> queue = new LinkedList<>();
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queue.add(root);
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List<List<Integer>> result = new ArrayList<>();
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while (!queue.isEmpty()) {
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int size = queue.size();
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List<Integer> list = new ArrayList<>();
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for (int i = 0; i < size; i++) {
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Node node = queue.poll();
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list.add(node.val);
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List<Node> nodeList = node.children;
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for (Node temp : nodeList) {
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queue.add(temp);
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}
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}
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result.add(list);
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}
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return result;
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}
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}
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//leetcode submit region end(Prohibit modification and deletion)
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} |