剑指-二叉树镜像

static class BinaryTreeNode {
int value;
BinaryTreeNode left;
BinaryTreeNode right;
}

private static void mirrorRecursively(BinaryTreeNode head) {
if (head == null) {
return;
}
if (head.left == null && head.right == null) {
return;
}

BinaryTreeNode temp = head.left;
head.left = head.right;
head.right = temp;

if (head.left != null) {
mirrorRecursively(head.left);
}

if (head.right != null) {
mirrorRecursively(head.right);
}
}