LeetCode OJ 108. Convert Sorted Array to Binary Search Tree DFS求解

Posted 2020-06-16 bruce128

    题目链接：https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/

108. Convert Sorted Array to Binary Search Tree

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Total Accepted: 68378 Total Submissions: 187560 Difficulty: Medium

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

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    很有意思的一道题目。要求根据一个有序数组，构造出一棵高度平衡的BST。

    每次找到数组的中间位置，这个便是BST的 根节点。左右孩子也很好找，根节点左边区域的中间节点便是左孩子，根节点的右边区域的中间节点便是右孩子。如此递归求解。

    我的AC代码

public class ConvertSortedArraytoBinarySearchTree {

	public TreeNode sortedArrayToBST(int[] nums) {
		return dfs(nums, 0, nums.length - 1);
	}

	TreeNode dfs(int[] nums, int left, int right) {
		if (left > right) return null;
		int mid = (left + right) / 2;
		TreeNode root = new TreeNode(nums[mid]);
		root.left = dfs(nums, left, mid - 1);
		root.right = dfs(nums, mid + 1, right);
		return root;
	}
}