Leetcode#108 Convert Sorted Array to Binary Search Tree

原题地址

对于已排序数组，二分法递归构造BST

代码：

 TreeNode *buildBST(vector<int> &num, int i, int j) {
   if (i > j)
     return NULL;

   int m = (i + j) /;
   TreeNode *node = new TreeNode(num[m]);
   node->left = buildBST(num, i, m - );
   node->right = buildBST(num, m + , j);

   return node;
 }

 TreeNode *sortedArrayToBST(vector<int> &num) {
   return buildBST(num, , num.size() - );
 }