226. Invert Binary Tree

三刷

100.00 %
class Solution {
    public TreeNode invertTree(TreeNode root) {
        if (root != null) {
            TreeNode left = root.left;
            root.left = invertTree(root.right);
            root.right = invertTree(left);
        }
        return root;
    }
}

二刷
完全一样
27.47 %
public class Solution {
    public TreeNode invertTree(TreeNode root) {
        if (root == null) return null;
        TreeNode left = invertTree(root.left);
        TreeNode right = invertTree(root.right);
        root.left = right;
        root.right = left;
        return root;
    }
}

一刷
/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public TreeNode invertTree(TreeNode root) {
        if (root == null) return root;
        TreeNode left = invertTree(root.left);
        TreeNode right = invertTree(root.right);
        root.left = right;
        root.right = left;
        return root;
    }
}