You need to find the largest value in each row of a binary tree.
Example:
Input: 1 / / 3 2 / / / 5 3 9 Output: [1, 3, 9]还是做好行遍历就行了，代码与[Find Bottom Left Tree Value]的结构基本相似，做好每一行的最大值存储即可：
public class FindLargestValueinEachTreeRow { public static List<Integer> largestValues(TreeNode root) { List<Integer> res = new ArrayList<>(); if (root == null) return res; res.add(root.val); LinkedList<TreeNode> levelNodes = new LinkedList<>(); if (root.left == null && root.right == null) { return res; } levelNodes.add(root); while (!levelNodes.isEmpty()) { LinkedList<TreeNode> tempLevel = new LinkedList<>(); for (TreeNode node : levelNodes) { if (node.left != null) tempLevel.add(node.left); if (node.right != null) tempLevel.add(node.right); } if (!tempLevel.isEmpty()) { int max = (int) (tempLevel.get(0).val); for (TreeNode node : tempLevel) { if (node.val > max) max = node.val; } res.add(max); levelNodes.clear(); levelNodes.addAll(tempLevel); } else { break; } } return res; } public static void main(String[] args) { TreeNode root = new TreeNode(1); root.left = new TreeNode(3); root.right = new TreeNode(2); root.left.left = new TreeNode(5); root.left.right = new TreeNode(3); root.right.right = new TreeNode(9); System.out.PRintln(largestValues(root)); }}新闻热点
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