Create Convert Sorted List to Binary Search Tree.java

Author: Lokesh598

Tree/Binary Search Tree/Convert Sorted List to Binary Search Tree.java

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+class Solution {
+    public TreeNode sortedListToBST(ListNode head) {
+        if (head == null) 
+            return null;
+        return toBST(head, null);
+    }
+    public TreeNode toBST(ListNode head, ListNode tail) {
+        
+        ListNode slow = head;
+        ListNode fast = head;
+        if (head==tail) return null;
+        while (fast!=tail && fast.next!=tail) {
+            slow = slow.next;
+            fast = fast.next.next;
+        }
+
+        TreeNode tree = new TreeNode(slow.val);
+        tree.left = toBST(head, slow);
+        tree.right = toBST(slow.next, tail);
+        return tree;
+    }
+}