劍指offer_編程題_二叉樹的鏡像

• 題目

  操作給定的二叉樹，將其變換爲源二叉樹的鏡像。
  二叉樹的鏡像定義：源二叉樹 
      	    8
      	   /  \
      	  6   10
      	 / \  / \
      	5  7  9 11
      	鏡像二叉樹
      	    8
      	   /  \
      	  10   6
      	 / \  / \
      	11 9  7  5
  

1. 對二叉樹進行遍歷，並交換左右孩子結點
   遞歸

   /*
   struct TreeNode {
       int val;
       struct TreeNode *left;
   	struct TreeNode *right;
   	TreeNode(int x) :
       		val(x), left(NULL), right(NULL) {
   	}
   };*/
   class Solution {
   public:
       void Mirror(TreeNode *pRoot) {
       	if(pRoot != NULL)
       	{
       		TreeNode *temp;
       		temp = pRoot->left;
       		pRoot->left = pRoot->right;
       		pRoot->right = temp;
       		Mirror(pRoot->left);
       		Mirror(pRoot->right);
       	}
       }
   };
   

2. 非遞歸層次遍歷

   /*
   struct TreeNode {
   	int val;
   	struct TreeNode *left;
   	struct TreeNode *right;
   	TreeNode(int x) :
   			val(x), left(NULL), right(NULL) {
   	}
   };*/
   class Solution {
   public:
       void Mirror(TreeNode *pRoot) {
    	   if(pRoot != NULL)
    	   {
    	       std::queue<TreeNode*> q;
    		   q.push(pRoot);
    		   while(!q.empty())
    		   {
    			   TreeNode *k = q.front();
    			   TreeNode *temp = k->left;
    			   k->left = k->right;
    			   k->right = temp;
    			   if(k->left!=NULL)
    				   q.push(k->left);
    			   if(k->right!=NULL)
    				   q.push(k->right);
    			   q.pop();
    		   }
    	   }
       }
   };