题目:
解答:
反转一颗空树结果还是一颗空树。对于一颗根为 rr,左子树为 \mbox{right}, 右子树为 \mbox{left} 的树来说,它的反转树是一颗根为 rr,左子树为{right} 的反转树,右子树为 {left} 的反转树的树。
1 /** 2 * Definition for a binary tree node. 3 * struct TreeNode { 4 * int val; 5 * TreeNode *left; 6 * TreeNode *right; 7 * TreeNode(int x) : val(x), left(NULL), right(NULL) {} 8 * }; 9 */ 10 class Solution { 11 public: 12 TreeNode* invertTree(TreeNode* root) 13 { 14 if (NULL == root) 15 { 16 return root; 17 } 18 TreeNode *right = invertTree(root->right); 19 TreeNode *left = invertTree(root->left); 20 root->left = right; 21 root->right = left; 22 return root; 23 24 } 25 };