populating next right pointer in each node

Author: chen0040

.idea/workspace.xml

@@ -0,0 +1,43 @@
+package com.github.chen0040.leetcode.day18.medium;
+
+
+import java.util.HashMap;
+import java.util.Map;
+
+
+/**
+ * Created by xschen on 13/8/2017.
+ *
+ * link: https://leetcode.com/problems/populating-next-right-pointers-in-each-node/description/
+ */
+public class PopulatingNextRightPointerInEachNode {
+    public class TreeLinkNode {
+      int val;
+      TreeLinkNode left, right, next;
+      TreeLinkNode(int x) { val = x; }
+  }
+
+   public class Solution {
+      Map<Integer, TreeLinkNode> levels = new HashMap<Integer, TreeLinkNode>();
+      public void connect(TreeLinkNode root) {
+         connect(root, 0);
+      }
+
+      private void connect(TreeLinkNode x, int d) {
+         if(x == null) {
+            return;
+         }
+
+         connect(x.left, d+1);
+
+         if(levels.containsKey(d)) {
+            levels.get(d).next = x;
+            levels.put(d, x);
+         } else {
+            levels.put(d, x);
+         }
+
+         connect(x.right, d+1);
+      }
+   }
+}