algorithm/Week_03/id_121/LeetCode_429_121.java at master · feixiangcode/algorithm · GitHub

38 lines (35 loc) · 935 Bytes

// Definition for a Node.

class Node {

public int val;

public List<Node> children;

public Node() {}

public Node(int _val,List<Node> _children) {

val = _val;

children = _children;

}

};

class Solution {

public List<List<Integer>> levelOrder(Node root) {

List<List<Integer>> ret = new LinkedList<>();

if(root == null){

return ret;

}

Queue<Node> queue = new LinkedList<Node>();

queue.offer(root);

while(!queue.isEmpty()){

List<Integer> currLevel = new LinkedList<Integer>();

int len = queue.size();

for(int i = 0;i < len;i ++){

Node curr = queue.poll();

currLevel.add(curr.val);

for(Node c : curr.children ){

queue.offer(c);

}

ret.add(currLevel);

}

return ret;

}

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