二叉搜索樹與雙向鏈表

• 輸入一棵二叉搜索樹，將該二叉搜索樹轉換成一個排序的雙向鏈表。要求不能建立任何新的結點，只能調整樹中結點指針的指向。

/*
struct TreeNode {
	int val;
	struct TreeNode *left;
	struct TreeNode *right;
	TreeNode(int x) :
			val(x), left(NULL), right(NULL) {
	}
};*/
class Solution {
public:
    TreeNode* Convert(TreeNode* pRootOfTree)
    {
        if(!pRootOfTree)
            return NULL;
        return ConvertTree(pRootOfTree, true);
    }
    
    TreeNode* ConvertTree(TreeNode * root, bool isRight){
        if(!root)
            return NULL;
        TreeNode * left = ConvertTree(root->left, false);
        TreeNode * right = ConvertTree(root->right, true);
        root->left = left;
        if(left)
            left->right = root;
        root->right = right;
        if(right)
            right->left = root;
        if(isRight){
            while(root->left)
                root = root->left;
        }else{
            while(root->right)
                root = root->right;
        }
        return root;
    }
};