convert-sorted-array-to-binary-s

class Solution {
public:
    TreeNode *sortedArrayToBST(vector<int> &num) {
        return create(num,0,num.size()-1);
    }
    TreeNode* create(vector<int>num,int L,int R)
    {
        if(L>R)return NULL;
        int mid=(R+L+1)/2;
//BST树总是从左到右排满的，如果不优先选右边的这个，{1,3}结果为{1，#，3}，而实际结果应为{3,1}
        TreeNode*root=new TreeNode(num[mid]);
        root->left=create(num,L,mid-1);
        root->right=create(num,mid+1,R);
        return root;
    }
};