《剑指Offer》

2016.02.16

程序员面试题精选100题(01)－把二元查找树转变成排序的双向链表[数据结构]

/*
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 == NULL) return pRootOfTree;
        pRootOfTree = ConvertNode(pRootOfTree);
        while(pRootOfTree->left) pRootOfTree = pRootOfTree->left;
        return pRootOfTree;
    }

    TreeNode* ConvertNode(TreeNode* root)
    {
        if(root == NULL) return root;
        if(root->left)
        {
            TreeNode *left = ConvertNode(root->left);
            while(left->right) left = left->right;
            left->right = root;
            root->left = left;
        }
        
        if(root->right)
        {
            TreeNode *right = ConvertNode(root->right);
            while(right->left) right = right->left;
            right->left = root;
            root->right = right;
        }
        return root;
    }
};