LeetCode（剑指 Offer）- 32 - I. 从上到下打印二叉树

题目链接：点击打开链接

题目大意：略

解题思路：略

相关企业

• 字节跳动

AC 代码

• Java

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public int[] levelOrder(TreeNode root) {
        if(root == null) return new int[0];
        Queue<TreeNode> queue = new LinkedList<>(){
   
   { add(root); }};
        ArrayList<Integer> ans = new ArrayList<>();
        while(!queue.isEmpty()) {
            TreeNode node = queue.poll();
            ans.add(node.val);
            if(node.left != null) queue.add(node.left);
            if(node.right != null) queue.add(node.right);
        }
        int[] res = new int[ans.size()];
        for(int i = 0; i < ans.size(); i++)
            res[i] = ans.get(i);
        return res;
    }
}

• C++

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    vector<int> levelOrder(TreeNode* root) {
        vector<int> res;
        if(!root) return res;
        queue<TreeNode*> que;
        que.push(root);
        while(!que.empty()){
            TreeNode* node = que.front();
            que.pop();
            res.push_back(node->val);
            if(node->left) que.push(node->left);
            if(node->right) que.push(node->right);
        }
        return res;
    }
};