日常水题（腾讯秋招50道）

Author: programmerhjh

src/entity/TreeNode.java

@@ -0,0 +1,9 @@
+package entity;
+
+public class TreeNode {
+     public int val;
+     public TreeNode left;
+     public TreeNode right;
+     TreeNode(int x) { val = x; }
+}
+	

src/myleetcode/LowestCommonAncestorOfABinarySearchTree.java

@@ -0,0 +1,28 @@
+package myleetcode;
+
+import entity.TreeNode;
+
+/**
+ * 二叉搜索树的最近公共祖先
+ * @author acer
+ *
+ */
+public class LowestCommonAncestorOfABinarySearchTree {
+
+	TreeNode res = null;
+
+	public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
+		lca(root, p, q);
+		return res;
+	}
+
+	public void lca(TreeNode root, TreeNode p, TreeNode q) {
+		if ((root.val - p.val) * (root.val - q.val) <= 0) {
+			res = root;
+		} else if (root.val < p.val && root.val < q.val) {
+			lca(root.right, p, q);
+		} else {
+			lca(root.left, p, q);
+		}
+	}
+}