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NAryTreeLevelOrderTraversal.java
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NAryTreeLevelOrderTraversal.java
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package com.dbc;
import javafx.util.Pair;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
public class NAryTreeLevelOrderTraversal {
class Node {
public int val;
public List<Node> children;
public Node() {
}
public Node(int _val) {
val = _val;
}
public Node(int _val, List<Node> _children) {
val = _val;
children = _children;
}
}
public List<List<Integer>> levelOrder(Node root) {
List<List<Integer>> res = new ArrayList<>();
if (root == null) return res;
int level = 1;
Queue<Pair<Integer, Node>> queue = new LinkedList<>();
queue.add(new Pair<>(level, root));
while (!queue.isEmpty()) {
Pair<Integer, Node> node = queue.poll();
level = node.getKey();
if (res.size() < level) {
res.add(new ArrayList<>());
}
res.get(level - 1).add(node.getValue().val);
for (Node item : node.getValue().children) {
queue.add(new Pair<>(level + 1, item));
}
}
return res;
}
}