/**

* @program JavaBooks

* @description: 将有序数组转成二叉搜索树

* @author: mf

* @create: 2020/03/09 17:06

*/

package subject.tree;

public class T4 {

/**

* 中序逆遍历

* @param nums

* @return

*/

public TreeNode sortedArrayToBST(int[] nums) {

return nums == null ? null : buildTreee(nums, 0, nums.length - 1);

}

public TreeNode buildTreee(int[] nums, int l, int r) {

if (l > r) return null;

int m = l + (r - l) / 2;

// left -> root -> right

TreeNode root = new TreeNode(nums[m]); // new一个root

root.left = buildTreee(nums, l, m - 1);

root.right = buildTreee(nums, m + 1, r);

return root;

}

}