108. Convert Sorted Array to Binary Search Tree - Easy

前往題目

想法

• 也是很久以前做過的題目了，但完全忘了怎麼寫

思路

1. binary search就可以建構出這個tree

Code

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

    private TreeNode createTree(int[] nums, int l, int r) {
        if (l > r) return null;

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

        TreeNode res = new TreeNode(nums[mid]);
        res.left = createTree(nums, l, mid - 1);
        res.right = createTree(nums, mid + 1, r);

        return res;
    }
}

2024/10/17

• 忘了怎麼找要插入的數:D