拼多多笔试题：数组构造二叉搜索平衡树

leetcode.cn/problems/co…

class TreeNode {
      int val;
      TreeNode left;
      TreeNode right;
      TreeNode() {}
      TreeNode(int val) { this.val = val; }
      TreeNode(int val, TreeNode left, TreeNode right) {
          this.val = val;
          this.left = left;
          this.right = right;
      }
  }
  class Solution {
    public TreeNode sortedArrayToBST(int[] nums) {
        return dfs(nums,0,nums.length-1);
    }
    private TreeNode dfs(int[] nums,int left,int right){
        if(left>right) return null;
        int mid=left+right>>1;
        TreeNode root=new TreeNode(nums[mid]);
        root.left=dfs(nums,left,mid-1);
        root.right=dfs(nums,mid+1,right);
        return root;
    }
}