[LEET-0000] clean up

fishercoder1534 · fishercoder1534 · commit 254a64242475 · 2017-02-08T18:06:12.000-08:00
diff --git a/leetcode-algorithms/README.md b/leetcode-algorithms/README.md
@@ -139,6 +139,7 @@
 |225|[Implement Stack using Queues](https://leetcode.com/problems/implement-stack-using-queues/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/ImplementStackUsingQueues.java)| O(n)|O(n) | Easy| Stack, Queue
 |224|[Basic Calculator](https://leetcode.com/problems/basic-calculator/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/BasicCalculator.java)| ?|? | Hard| 
 |223|[Rectangle Area](https://leetcode.com/problems/rectangle-area/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/RectangleArea.java)| O(1)|O(1) | Easy| 
+|222|[Count Complete Tree Nodes](https://leetcode.com/problems/count-complete-tree-nodes/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/CountCompleteTreeNodes.java)| O(?)|O(h) | Medium|
 |220|[Contains Duplicate III](https://leetcode.com/problems/contains-duplicate-iii/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/ContainsDuplicateIII.java)| O(nlogn)|O(n) | Medium| TreeSet
 |219|[Contains Duplicate II](https://leetcode.com/problems/contains-duplicate-ii/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/ContainsDuplicateII.java)| O(n)|O(n) | Easy| HashMap
 |217|[Contains Duplicate](https://leetcode.com/problems/contains-duplicate/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/ContainsDuplicate.java)| O(n)|O(n) | Easy| HashSet
@@ -176,7 +177,8 @@
 |151|[Reverse Words in a String](https://leetcode.com/problems/reverse-words-in-a-string/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/ReverseWordsinaString.java)| O(n)|O(n) | Medium|
 |150|[Evaluate Reverse Polish Notation](https://leetcode.com/problems/evaluate-reverse-polish-notation/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/EvaluateReversePolishNotation.java)| O(?)|O(?) | Medium
 |149|[Max Points on a Line](https://leetcode.com/problems/max-points-on-a-line/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/MaxPointsonaLine.java)| O(?)|O(?) | Hard|
-|147|[Insertion Sort List](https://leetcode.com/problems/insertion-sort-list/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/InsertionSortList.java)| O(n^2)|O(1) | Medium| Linked List
+|147|[Insertion Sort List](https://leetcode.com/problems/insertion-sort-list/)|[Doubly Linked List](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/InsertionSortList.java)|[Linked Hash Map](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/LRUCache_use_LinkedHashMap.java) O(n^2)|O(1) | Hard| Linked List
+|146|[LRU Cache](https://leetcode.com/problems/lru-cache/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/LRUCache_use_DoublyLinkedList_plus_HashMap.java)| O(?)|O(?) | Hard| Linked List
 |145|[Binary Tree Postorder Traversal](https://leetcode.com/problems/binary-tree-postorder-traversal/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/BinaryTreePostOrderTraversal.java)| O(n)|O(h) | Hard| Binary Tree
 |144|[Binary Tree Preorder Traversal](https://leetcode.com/problems/binary-tree-preorder-traversal/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/BinaryTreePreorderTraversal.java)| O(n)|O(h) | Medium| Binary Tree
 |143|[Reorder List](https://leetcode.com/problems/reorder-list/)|[Solution](../../master/leetcode-algorithms/src/main/java/com/stevesun/solutions/ReorderList.java)| O(n)|O(1) | Medium|
diff --git a/leetcode-algorithms/src/main/java/com/stevesun/solutions/CountCompleteTreeNodes.java b/leetcode-algorithms/src/main/java/com/stevesun/solutions/CountCompleteTreeNodes.java
@@ -0,0 +1,32 @@
+package com.stevesun.solutions;
+
+import com.stevesun.common.classes.TreeNode;
+
+/**
+ * Given a complete binary tree, count the number of nodes.
+ * <p>
+ * Definition of a complete binary tree from Wikipedia:
+ * In a complete binary tree every level, except possibly the last, is completely filled, and all nodes in the last level are as far left as possible. It can have between 1 and 2h nodes inclusive at the last level h.
+ */
+public class CountCompleteTreeNodes {
+
+    int height(TreeNode root) {
+        return root == null ? -1 : 1 + height(root.left);
+    }
+
+    public int countNodes(TreeNode root) {
+        int nodes = 0, h = height(root);
+        while (root != null) {
+            if (height(root.right) == h - 1) {
+                nodes += 1 << h;
+                root = root.right;
+            } else {
+                nodes += 1 << h - 1;
+                root = root.left;
+            }
+            h--;
+        }
+        return nodes;
+    }
+
+}
