剑指offer-3.3-32.1-优快云博客

本文链接：https://blog.youkuaiyun.com/Desperate_gh/article/details/114301093


        // return res.stream().mapToInt(Integer::valueOf).toArray();

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/**
 * 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<TreeNode>();
        queue.add(root);
        List<Integer> res = new ArrayList<Integer>();
        while (!queue.isEmpty()) {
            TreeNode cur = queue.poll();
            res.add(cur.val);
            if (cur.left != null) {
                queue.add(cur.left);
            }
            if (cur.right != null) {
                queue.add(cur.right);
            }
        }
        int[] ans = new int[res.size()];
        for (int i = 0; i < ans.length; i++) {
            ans[i] = res.get(i);
        }
        return ans;
    }
}

/**
 * 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<TreeNode>();
        queue.add(root);
        List<Integer> res = new ArrayList<Integer>();
        while (!queue.isEmpty()) {
            TreeNode cur = queue.poll();
            res.add(cur.val);
            if (cur.left != null) {
                queue.add(cur.left);
            }
            if (cur.right != null) {
                queue.add(cur.right);
            }
        }
        return res.stream().mapToInt(Integer::valueOf).toArray();
    }
}