【leetcode】Kth Smallest Element in a BST

Problem

Code

/**
* Definition for a binary tree node.
* struct TreeNode {
*     int val;
*     struct TreeNode *left;
*     struct TreeNode *right;
* };
*/
bool getTheNumber(struct TreeNode *root,int *num,int k,int *index){
if(root==NULL)  return false;
if(getTheNumber(root->left,num,k,index))
return true;
if(*index == k){
*num = root->val;
return true;
}
++(*index);
if(getTheNumber(root->right,num,k,index))
return true;
return false;
}
int kthSmallest(struct TreeNode* root, int k) {
int index = 1,num = 0;
getTheNumber(root,&num,k,&index);
return num;
}

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