翻转一棵二叉树（非递归版本）
public class Solution {
/**
* @param root: a TreeNode, the root of the binary tree
* @return: nothing
*/
public void invertBinaryTree(TreeNode root) {
// write your code here
if(root == null){
return;
}
Queue<TreeNode> queue = new LinkedList<TreeNode>();
queue.offer(root);
while(!queue.isEmpty()){
int size = queue.size();
for(int i = 0; i < size; i++){
TreeNode node = queue.poll();
TreeNode temp = node.left;
node.left = node.right;
node.right = temp;
if(node.left != null){
queue.offer(node.left);
}
if(node.right != null){
queue.offer(node.right);
}
}
}
}
}
解题思路：
通过队列将每个节点的左右子节点翻转
