Leetcode 226:Invert a binary tree

Leetcode—226

Invert a binary tree.

     4   /   \  2     7 / \   / \1   3 6   9

to

     4   /   \  7     2 / \   / \9   6 3   1

【题目大意】：反转二叉树
第一次在知乎看到这个题目背后的故事的时候觉得蛮惊奇的
【解法】：简单的二叉树遍历，后续遍历
【AC代码】：

/** * Definition for a binary tree node. * struct TreeNode { *     int val; *     struct TreeNode *left; *     struct TreeNode *right; * }; */struct TreeNode* invertTree(struct TreeNode* root) {    if(!root){        return NULL;    }    else{        struct TreeNode * rleft = invertTree(root -> left);        struct TreeNode * rright = invertTree(root -> right);        root ->left = rright;        root ->right = rleft;        return root;    }}