Added convert sorted array to bst - easy

MichaelVandi · MichaelVandi · commit 557ad837e894 · 2020-10-06T17:31:50.000-04:00
diff --git a/Easy/10_06_2020_convert_sorted_array_to_bst.java b/Easy/10_06_2020_convert_sorted_array_to_bst.java
@@ -0,0 +1,28 @@
+/**
+ * Time: O(log (n))
+ * Space: O(n)
+ */
+class Solution {
+    public TreeNode sortedArrayToBST(int[] nums) {
+        if (nums.length == 0 || nums == null) return null;
+        return convert(nums, 0, nums.length - 1);
+    }
+    public TreeNode convert(int[] array, int start, int end) {
+        if (start > end) return null;
+        // Calculate median index
+        int mid = start + (end - start) / 2;
+        // Set median val to root
+        TreeNode root = new TreeNode(array[mid]);
+        // Determine left and right children
+        // S for 'start', m for 'mid' and e for 'end'
+        //  s           m           e
+        //  x - x - x - x - x - x - x
+        // You can see that the left side ranges from start to mid
+        // And right side ranges from mid to end
+        root.left = convert(array, start, mid - 1);
+        root.right = convert(array, mid + 1, end);
+        return root;
+    }
+    
+    
+}
