Invert Binary Tree @LeetCode

PROBLEM :

Invert a binary tree.

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

to

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

--------------------------------------------------------------------------------
SIMPLE c++ IMPLEMENTATION :( Recursive Solution )
--------------------------------------------------------------------------------

 /**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */

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

--------------------------------------------------------------------------------
SIMPLE c++ IMPLEMENTATION :( Iterative Solution )
--------------------------------------------------------------------------------

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */

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

---------------------------------------------------------------------------------

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