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Solution.java
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Solution.java
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package g0101_0200.s0108_convert_sorted_array_to_binary_search_tree;
// #Easy #Top_Interview_Questions #Array #Tree #Binary_Tree #Binary_Search_Tree #Divide_and_Conquer
// #Data_Structure_II_Day_15_Tree #Level_2_Day_9_Binary_Search_Tree #Udemy_Tree_Stack_Queue
// #2022_06_22_Time_0_ms_(100.00%)_Space_43.9_MB_(32.26%)
import com_github_leetcode.TreeNode;
/*
* Definition for a binary tree node.
* public 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;
* }
* }
*/
public class Solution {
public TreeNode sortedArrayToBST(int[] num) {
/*1. Set up recursion*/
return makeTree(num, 0, num.length - 1);
}
private TreeNode makeTree(int[] num, int left, int right) {
/*2. left as lowest# can't be greater than right*/
if (left > right) {
return null;
}
/*3. Set median# as node*/
int mid = (left + right) / 2;
TreeNode midNode = new TreeNode(num[mid]);
/*4. Set mid node's kids*/
midNode.left = makeTree(num, left, mid - 1);
midNode.right = makeTree(num, mid + 1, right);
/*5. Sends node back || Goes back to prev node*/
return midNode;
}
}