03.01 (1) insert into BST

stevencooks · stevencooks · commit 46b313b83427 · 2015-08-26T15:42:52.000-04:00
diff --git a/03_binarytree&divideconquer/InsertNodeInABinarySearchTree/Solution.java b/03_binarytree&divideconquer/InsertNodeInABinarySearchTree/Solution.java
@@ -0,0 +1,44 @@
+/**
+ * Time : O() ; Space: O()
+ * @tag : LintCode Copyright; Binary Search Tree
+ * @by  : Steven Cooks
+ * @date: Aug 26, 2015
+ ***************************************************************************
+ * Description:
+ *
+ * 
+ ***************************************************************************
+ * {@link http://www.lintcode.com/en/problem/insert-node-in-a-binary-search-tree/# }
+ */
+package InsertNodeInABinarySearchTree;
+
+import com.leetcode.TreeNode;
+
+/** see test {@link InsertNodeInABinarySearchTree.SolutionTest } */
+public class Solution {
+
+    public TreeNode insertNode(TreeNode root, TreeNode node) {
+        TreeNode x = root;
+        while (x != null) {
+            if (x.val > node.val) {
+                if (x.left == null) {
+                    x.left = node;
+                    return root;
+                } else {
+                    x = x.left;
+                }
+            } else if (x.val < node.val) {
+                if (x.right == null) {
+                    x.right = node;
+                    return root;
+                } else {
+                    x = x.right;
+                }
+            } else {
+                return root;
+            }
+        }
+        return node;
+    }
+
+}
diff --git a/03_binarytree&divideconquer/InsertNodeInABinarySearchTree/SolutionTest.java b/03_binarytree&divideconquer/InsertNodeInABinarySearchTree/SolutionTest.java
@@ -0,0 +1,67 @@
+package InsertNodeInABinarySearchTree;
+
+import static org.junit.Assert.*;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.Timeout;
+
+import com.leetcode.TreeNode;
+
+public class SolutionTest {
+    
+    /** Test method for {@link InsertNodeInABinarySearchTree.Solution } */
+    Solution solution;
+
+    @Rule
+    public Timeout globalTimeout = new Timeout(200);
+
+    @Before
+    public void setUp() throws Exception {
+        solution = new Solution();
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        solution = null;
+    }
+
+    // null  =>  1
+    @Test
+    public void Test1() {
+        TreeNode root = null;
+        TreeNode node = new TreeNode(1);
+        TreeNode actual = solution.insertNode(root, node);
+        TreeNode expected = new TreeNode(1);
+        assertTrue(TreeNode.isSameTree(actual, expected));
+    }
+
+    //  1   =>  1
+    //            \
+    //             2
+    @Test
+    public void Test2() {
+        TreeNode root = new TreeNode(1);
+        TreeNode node = new TreeNode(2);
+        TreeNode actual = solution.insertNode(root, node);
+        TreeNode expected = new TreeNode(1);
+        expected.right = new TreeNode(2);
+        assertTrue(TreeNode.isSameTree(actual, expected));
+    }
+
+    //  3   =>   3
+    //          /
+    //         2 
+    @Test
+    public void Test3() {
+        TreeNode root = new TreeNode(3);
+        TreeNode node = new TreeNode(2);
+        TreeNode actual = solution.insertNode(root, node);
+        TreeNode expected = new TreeNode(3);
+        expected.left = new TreeNode(2);
+        assertTrue(TreeNode.isSameTree(actual, expected));
+    }
+
+}
diff --git a/src/com/leetcode/TreeNode.java b/src/com/leetcode/TreeNode.java
