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Convert Sorted Array to Binary Search Tree (BST)

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Given an integer array nums where the elements are sorted in ascending order, convert it to a height-balanced binary search tree.

public TreeNode sortedArrayToBST(int[] num) {
    if (num.length == 0) {
        return null;
    TreeNode head = helper(num, 0, num.length - 1);
    return head;

public TreeNode helper(int[] num, int low, int high) {
    if (low > high) { // Done
        return null;
    int mid = (low + high) / 2;
    TreeNode node = new TreeNode(num[mid]);
    node.left = helper(num, low, mid - 1);
    node.right = helper(num, mid + 1, high);
    return node;

Posted by Jamie Meyer 3 months ago

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