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| class TreeNode{
int val = 0;
TreeNode left = null;
TreeNode right = null;
public TreeNode(int val){
this.val = val;
}
}
public class BSTToLinkedList{
public TreeNode convert(TreeNode root){
if(root == null){
return null;
}
TreeNode head = new TreeNode(0);
TreeNode prev = new TreeNode(0);
convertHelper(TreeNode root, TreeNode head, TreeNode prev);
return head.left;
}
private void convertHelper(TreeNode root, TreeNode head, TreeNode prev){
if(root == null){
return;
}
convertHelper(root.left, head, prev);
if(head.left == null){
head.left = root;
}
if(prev.left == null){
prev.left = root;
}else{
prev.left.right = root;
root.left = prev.left;
prev.left = root;
}
convertHelper(root.right, head, prev);
}
}
|