public static void main(String[] args) {
BiTreeNode root = new BiTreeNode(1);
root.lchild = new BiTreeNode(2);
root.lchild.lchild = new BiTreeNode(4);
root.lchild.rchild = new BiTreeNode(5);
root.lchild.rchild.rchild = new BiTreeNode(9);
root.lchild.lchild.lchild = new BiTreeNode(8);
root.rchild = new BiTreeNode(3);
root.rchild.lchild = new BiTreeNode(6);
root.rchild.rchild = new BiTreeNode(7);
root.rchild.rchild.lchild = new BiTreeNode(10);
root = mirror(root);
BinaryTreeTravel2.inTravel(root);
System.out.println();
BinaryTreeTravel2.preTravel(root);
root = new BiTreeNode(1);
root.lchild = new BiTreeNode(2);
root.lchild.lchild = new BiTreeNode(4);
root.lchild.rchild = new BiTreeNode(5);
root.lchild.rchild.rchild = new BiTreeNode(9);
root.lchild.lchild.lchild = new BiTreeNode(8);
root.rchild = new BiTreeNode(3);
root.rchild.lchild = new BiTreeNode(6);
root.rchild.rchild = new BiTreeNode(7);
root.rchild.rchild.lchild = new BiTreeNode(10);
root = mirror2(root);
System.out.println();
BinaryTreeTravel2.inTravel(root);
System.out.println();
BinaryTreeTravel2.preTravel(root);
}
/**
* 求二叉树的镜像
*
* @param root
* @return
*/
public static BiTreeNode mirror(BiTreeNode root) {
if (root == null) return null;
if (root.lchild == null && root.rchild == null) {
return root;
}
// else {
// BiTreeNode tmp = root.lchild;
// root.lchild = root.rchild;
// root.rchild = tmp;
// }
BiTreeNode lmirror = mirror(root.lchild);
BiTreeNode rmirror = mirror(root.rchild);
root.lchild = rmirror;
root.rchild = lmirror;
return root;
}
/**
* 非递归法求镜像
*
* @param root
* @return
*/
public static BiTreeNode mirror2(BiTreeNode root) {
if (root == null) return null;
Stack<BiTreeNode> stack = new Stack<BiTreeNode>();
BiTreeNode p = root;
stack.push(p);
while (!stack.isEmpty()) {
p = stack.pop();
if (p.lchild != null || p.rchild != null) {
BiTreeNode tmp = p.lchild;
p.lchild = p.rchild;
p.rchild = tmp;
}
if (p.lchild != null) stack.push(p.lchild);
if (p.rchild != null) stack.push(p.rchild);
}
return root;
}