03.02 (1) search range on BST using pruning

stevencooks · stevencooks · commit e5b9fb7bd30e · 2015-09-01T10:09:26.000-04:00
diff --git a/03_binarytree&divideconquer/_02_SearchRangeInBinarySearchTree/Solution.java b/03_binarytree&divideconquer/_02_SearchRangeInBinarySearchTree/Solution.java
@@ -0,0 +1,51 @@
+/**
+ * Time : O() ; Space: O()
+ * @tag : Binary Search Tree
+ * @by  : Steven Cooks
+ * @date: Sep 1, 2015
+ ***************************************************************************
+ * Description:
+ * 
+ * Given two values k1 and k2 (where k1 < k2) and a root pointer to a Binary 
+ * Search Tree. Find all the keys of tree in range k1 to k2. i.e. print all 
+ * x such that k1<=x<=k2 and x is a key of given BST. Return all the keys 
+ * in ascending order.
+ *
+ ***************************************************************************
+ * {@link http://www.lintcode.com/en/problem/search-range-in-binary-search-tree/ }
+ */
+package _02_SearchRangeInBinarySearchTree;
+
+import java.util.ArrayList;
+
+import com.leetcode.TreeNode;
+
+/** see test {@link _02_SearchRangeInBinarySearchTree.SolutionTest } */
+public class Solution {
+
+    /**
+     * @param root: The root of the binary search tree.
+     * @param k1 and k2: range k1 to k2.
+     * @return: Return all keys that k1<=key<=k2 in ascending order.
+     */
+    public ArrayList<Integer> searchRange(TreeNode root, int k1, int k2) {
+        ArrayList<Integer> res = new ArrayList<>();
+        if (root == null) {
+            return res;
+        }
+        int val = root.val;
+        if (val >= k1) {
+            // pruning
+            res.addAll(searchRange(root.left, k1, k2));
+        }
+        if (val >= k1 && val <= k2) {
+            res.add(val);
+        }
+        if (val <= k2) {
+            // pruning
+            res.addAll(searchRange(root.right, k1, k2));
+        }
+        return res;
+    }
+
+}
diff --git a/03_binarytree&divideconquer/_02_SearchRangeInBinarySearchTree/SolutionTest.java b/03_binarytree&divideconquer/_02_SearchRangeInBinarySearchTree/SolutionTest.java
@@ -0,0 +1,96 @@
+package _02_SearchRangeInBinarySearchTree;
+
+import static org.junit.Assert.*;
+
+import java.util.ArrayList;
+
+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 _02_SearchRangeInBinarySearchTree.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;
+    }
+
+    //   1
+    @Test
+    public void Test1() {
+        TreeNode root = TreeNode.getBST1();
+        int k1 = 0;
+        int k2 = 2;
+        ArrayList<Integer> actual = solution.searchRange(root, k1, k2);
+        ArrayList<Integer> expected = new ArrayList<>();
+        expected.add(1);
+        assertEquals(expected, actual);
+    }
+
+    //   1 
+    //    \
+    //     2
+    //      \
+    //       3 
+    @Test
+    public void Test2() {
+        TreeNode root = TreeNode.getBST2();
+        int k1 = 1;
+        int k2 = 2;
+        ArrayList<Integer> actual = solution.searchRange(root, k1, k2);
+        ArrayList<Integer> expected = new ArrayList<>();
+        expected.add(1);
+        expected.add(2);
+        assertEquals(expected, actual);
+    }
+
+    //      10
+    //     /  \
+    //    5   12
+    //   / \
+    //  4   7
+    @Test
+    public void Test3() {
+        TreeNode root = TreeNode.getBST5();
+        int k1 = 6;
+        int k2 = 13;
+        ArrayList<Integer> actual = solution.searchRange(root, k1, k2);
+        ArrayList<Integer> expected = new ArrayList<>();
+        expected.add(7);
+        expected.add(10);
+        expected.add(12);
+        assertEquals(expected, actual);
+    }
+
+    //      2 
+    //    /   \
+    //   1     3
+    @Test
+    public void Test4() {
+        TreeNode root = TreeNode.getBST4();
+        int k1 = 0;
+        int k2 = 5;
+        ArrayList<Integer> actual = solution.searchRange(root, k1, k2);
+        ArrayList<Integer> expected = new ArrayList<>();
+        expected.add(1);
+        expected.add(2);
+        expected.add(3);
+        assertEquals(expected, actual);
+    }
+
+}
