[leetcode]: 226. Invert Binary Tree

1.题目

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

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

2.分析

3.代码

class Solution {
public:
TreeNode* invertTree(TreeNode* root) {
if (root == NULL)
return root;
TreeNode* tempL= invertTree(root->right);
TreeNode* tempR = invertTree(root->left);
root->left = tempL;
root->right = tempR;
return root;
}
};

class Solution {
public:
TreeNode* invertTree(TreeNode* root) {
if (root == NULL)
return root;
queue<TreeNode*> nodes;
nodes.push(root);
while (!nodes.empty()) {
TreeNode* node = nodes.front();
nodes.pop();
if (node->left != NULL)
nodes.push(node->left);
if (node->right != NULL)
nodes.push(node->right);
TreeNode* temp = node->left;
node->left = node->right;
node->right = temp;
}
return root;
}
};