add lca of bst and pal linked list

Author: tg123

lowest-common-ancestor-of-a-binary-search-tree/README.md

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+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+public class Solution {
+    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
+        // make sure p < q
+        if(p.val > q.val) return lowestCommonAncestor(root, q, p);
+
+        // find p <= root <= q
+        while(!(p.val <= root.val && root.val <= q.val)){
+
+            if(root.val > q.val){
+                root = root.left;
+            } else { // root.val < p.val
+                root = root.right;
+            }
+
+        }
+
+        return root;
+    }
+}

lowest-common-ancestor-of-a-binary-search-tree/Solution.java

@@ -0,0 +1,7 @@
+---
+layout: solution
+title: Lowest Common Ancestor of a Binary Search Tree
+date: 2015-07-12 16:47:16+08:00
+leetcode_id: 235
+---
+{% include_relative README.md %}

lowest-common-ancestor-of-a-binary-search-tree/index.md

@@ -0,0 +1,56 @@
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode(int x) { val = x; }
+ * }
+ */
+public class Solution {
+    ListNode mid(ListNode head){
+
+        ListNode fast = head;
+        ListNode slow = head;
+
+        while(fast != null && fast.next != null){
+            fast = fast.next.next;
+            slow = slow.next;
+        }
+
+        return slow;
+    }
+
+    ListNode reverse(ListNode head) {
+        ListNode prev = null;
+
+        while(head != null){
+
+            ListNode t = head.next;
+
+            head.next = prev;
+            prev = head;
+
+            head = t;
+        }
+
+        return prev;
+    }
+
+    public boolean isPalindrome(ListNode head) {
+        ListNode m = mid(head);
+
+        m = reverse(m);
+
+        while(m != head && m != null){
+
+            if(m.val != head.val){
+                return false;
+            }
+
+            m = m.next;
+            head = head.next;
+        }
+
+        return true;
+    }
+}

palindrome-linked-list/README.md

@@ -0,0 +1,7 @@
+---
+layout: solution
+title: Palindrome Linked List
+date: 2015-07-12 17:00:15+08:00
+leetcode_id: 234
+---
+{% include_relative README.md %}