Convert Sorted Array to Binary Search Tree，sortedbinary

Convert Sorted Array to Binary Search Tree，sortedbinary

Given an array where elements are sorted in ascending order, convert it to a height balanced BST.

基本思路：

由於隊列已經進行排序，每次取其中點，作為樹的根。

即可建得一棵平衡二叉樹。

/** * Definition for a binary tree node. * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    TreeNode* sortedArrayToBST(vector<int>& nums) {        return buildTree(nums, 0, nums.size());    }        TreeNode *buildTree(vector<int> &nums, int start, int stop) {        if (start >= stop) return 0;        int mid = start + (stop-start) / 2;        TreeNode *root = new TreeNode(nums[mid]);        root->left = buildTree(nums, start, mid);        root->right = buildTree(nums, mid+1, stop);        return root;    }};