0114.Flatten Binary Tree to LinkedList

Author: ChlZhYa

LeetCode/0114.Flatten Binary Tree to Linked List/src/Solution.java

@@ -0,0 +1,22 @@
+class Solution {
+    public void flatten(TreeNode root) {
+        if(root == null){
+            return;
+        }
+        merge(root);
+    }
+
+    public TreeNode merge(TreeNode node){
+        if(node == null){
+            return null;
+        }
+        TreeNode leftEnd =  merge(node.left);
+        TreeNode rightEnd = merge(node.right);
+        if(leftEnd != null){
+            leftEnd.right = node.right;
+            node.right = node.left;
+            node.left = null;
+        }
+        return rightEnd == null ? (leftEnd == null ? node : leftEnd) : rightEnd;
+    }
+}