InvertBinaryTree
InvertBinaryTree.java 源码
package datastructure.tree.leetcode;
import java.util.LinkedList;
import java.util.Queue;
/**
* @author roseduan
* @time 2021/9/20 6:07 下午
* @description 翻转二叉树
*/
public class InvertBinaryTree {
/**
* 递归
*/
public TreeNode invertTree(TreeNode root) {
if (root == null) {
return null;
}
TreeNode left = root.left;
root.left = root.right;
root.right = left;
invertTree(root.left);
invertTree(root.right);
return root;
}
/**
* 广度优先
*/
public TreeNode invertTree2(TreeNode root) {
if (root == null) {
return null;
}
Queue<TreeNode> queue = new LinkedList<>();
queue.add(root);
while (!queue.isEmpty()) {
TreeNode node = queue.poll();
TreeNode left = node.left;
node.left = node.right;
node.right = left;
if (node.left != null) {
queue.add(node.left);
}
if (node.right != null) {
queue.add(node.right);
}
}
return root;
}
public static class TreeNode {
int val;
TreeNode left;
TreeNode right;
TreeNode(int val, TreeNode left, TreeNode right) {
this.val = val;
this.left = left;
this.right = right;
}
}
}
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