public class Solution {ListNode getLeftNodeFromList(ListNode head){//默认就至少有2个链表节点ListNode next = head.next;ListNode index = head.next;ListNode pre = head;while(next != null){next = next.next;if(next == null) break;next = next.next;if(next == null) break;pre = pre.next;index = pre.next;}return pre;}public TreeNode sortedListToBST(ListNode head) {if(head == null) return null;if(head.next == null) return new TreeNode(head.val);ListNode left = getLeftNodeFromList(head);ListNode mid = left.next;left.next = null;TreeNode root = new TreeNode(mid.val);root.left = sortedListToBST(head);root.right = sortedListToBST(mid.next);return root;}
}

public int rank(Key key)
{int lo = 0, hi = N-1;while(lo <= hi){int mid = lo + (hi - lo)/2;int cmp = key.compareTo(Key[mid]);if        (cmp < 0) hi = mid - 1;else if (cmp > 0) lo = mid +1;else return mid;}return lo;
}

public int rank(Key key, int lo, int hi)
{if(hi < lo) return lo;int mid = lo + (hi - lo)/2;int cmp = key.compareTo(keys[mid]);if (cmp < 0) return rank(key, lo, mid-1);else if (cmp > 0) return rank(key, mid+1, hi);else return mid;
}

public class Solution {  static ListNode currentHead = null;  TreeNode buildTree(int start, int end) {  if(start>end) {  return null;  }  int mid = start + (end - start)/2;  TreeNode left = buildTree(start, mid-1);  TreeNode root = new TreeNode(currentHead.val);  root.left = left;  currentHead = currentHead.next;  root.right = buildTree(mid + 1, end);  return root;  }  public TreeNode sortedListToBST(ListNode head) {  if(head==null) {  return null;  }  currentHead = head;  int len = 0;  while(head!=null) {  len++;  head = head.next;  }  return buildTree(0, len-1);  }
}