一.題目
Convert Sorted Array to Binary Search Tree
Total Accepted: 44608 Total Submissions: 131357My SubmissionsGiven an array where elements are sorted in ascending order, convert it to a height balanced BST.
二.解題技巧
三.實現代碼
#include <iostream>
#include <vector>
using std::vector;
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
struct TreeNode
{
int val;
TreeNode *left;
TreeNode *right;
TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};
class Solution
{
private:
TreeNode* sortedArrayToBST(vector<int>::iterator Begin,
vector<int>::iterator End)
{
if (Begin == End)
{
return NULL;
}
vector<int>::iterator HeadIte = Begin + (End - Begin) / 2;
TreeNode *Head = new TreeNode(*HeadIte);
TreeNode *LeftChild = sortedArrayToBST(Begin, HeadIte);
TreeNode *RightChild = sortedArrayToBST(HeadIte + 1, End);
Head->left = LeftChild;
Head->right = RightChild;
return Head;
}
public:
TreeNode* sortedArrayToBST(vector<int>& nums)
{
return sortedArrayToBST(nums.begin(), nums.end());
}
};