226 - Invert Binary Tree
#easy
Given the root
of a binary tree, invert the tree, and return its root.
Example 1:
Input: root = [4,2,7,1,3,6,9]
Output: [4,7,2,9,6,3,1]
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
TreeNode* invertTree(TreeNode* root) {
queue<TreeNode*> que;
if ( root == NULL ) return NULL;
else que.push(root);
while ( !que.empty() ) {
TreeNode * cur = que.front();
que.pop();
swap( cur -> left, cur -> right );
if ( cur -> left != NULL ) que.push( cur -> left );
if ( cur -> right != NULL ) que.push( cur -> right );
}
return root;
}
};