[20161117]翻转二叉树

Google: 90% of our engineers use the software you wrote (Homebrew), but you can’t invert a binary tree on a whiteboard so fuck off.

内心复杂地做完了这道带有传奇色彩的题。。

代码如下：

struct TreeNode* invertTree(struct TreeNode* root) { struct TreeNode* p; if(!root) return NULL; else{ p = root -> left; root -> left = root -> right; root -> right = p; } invertTree(root -> left); invertTree(root -> right); return root; }