117. Populating Next Right Pointers in Each Node II (java)

Author: bluesword12350

solution/0117.Populating Next Right Pointers in Each Node II/Solution.java

@@ -0,0 +1,28 @@
+public class Solution {
+    public void connect(TreeLinkNode root) {
+        if (root == null) return;
+        TreeLinkNode first_node_next_layer = null;
+        TreeLinkNode preNode = null;
+        for (TreeLinkNode curNode = root; curNode != null; curNode = curNode.next) {
+            if (curNode.left != null) {
+                if (preNode == null) {
+                    preNode = curNode.left;
+                    first_node_next_layer = curNode.left;
+                } else {
+                    preNode.next = curNode.left;
+                    preNode = preNode.next;
+                }
+            }
+            if (curNode.right != null) {
+                if (preNode == null) {
+                    preNode = curNode.right;
+                    first_node_next_layer = curNode.right;
+                } else {
+                    preNode.next = curNode.right;
+                    preNode = preNode.next;
+                }
+            }
+        }
+        connect(first_node_next_layer);
+    }
+}