refactor 240

Author: fishercoder1534

README.md

@@ -379,7 +379,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |243|[Shortest Word Distance](https://leetcode.com/problems/shortest-word-distance/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_243.java) | O(n) | O(1) | Easy
 |242|[Valid Anagram](https://leetcode.com/problems/valid-anagram/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_242.java) | O(n) | O(1) | Easy
 |241|[Different Ways to Add Parentheses](https://leetcode.com/problems/different-ways-to-add-parentheses/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_241.java) | O(O(n * 4^n / n^(3/2))) | O(n * 4^n / n^(3/2)) | Medium | Divide and Conquer
-|240|[Search a 2D Matrix II](https://leetcode.com/problems/search-a-2d-matrix-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_240.java)| O(log(m*n))|O(1) | Medium| Binary Search
+|240|[Search a 2D Matrix II](https://leetcode.com/problems/search-a-2d-matrix-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_240.java)| O(m+n)|O(1) | Medium| Binary Search
 |239|[Sliding Window Maximum](https://leetcode.com/problems/sliding-window-maximum/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_239.java)| O(nlogn)|O(k) | Hard| Heap
 |238|[Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_238.java)| O(n)|O(1) | Medium| Array
 |237|[Delete Node in a Linked List](https://leetcode.com/problems/delete-node-in-a-linked-list/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_237.java)| O(1)|O(1) | Easy| LinkedList

src/main/java/com/fishercoder/solutions/_240.java

@@ -1,7 +1,10 @@
 package com.fishercoder.solutions;
 
 /**
- * Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:
+ * 240. Search a 2D Matrix II
+ *
+ * Write an efficient algorithm that searches for a value in an m x n matrix.
+ * This matrix has the following properties:
 
  Integers in each row are sorted in ascending from left to right.
  Integers in each column are sorted in ascending from top to bottom.
@@ -23,6 +26,9 @@
 public class _240 {
 
     public boolean searchMatrix(int[][] matrix, int target) {
+        if (matrix == null || matrix.length == 0) {
+            return false;
+        }
         int m = matrix.length;
         int n = matrix[0].length;
         int x = 0;

src/test/java/com/fishercoder/_240Test.java

@@ -0,0 +1,49 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._240;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static junit.framework.Assert.assertEquals;
+
+public class _240Test {
+    private static _240 test;
+    private static boolean actual;
+    private static boolean expected;
+    private static int target;
+    private static int[][] matrix;
+
+    @BeforeClass
+    public static void setup(){
+        test = new _240();
+    }
+
+    @Before
+    public void setupForEachTest(){
+    }
+
+    @Test
+    public void test1(){
+        target = 5;
+        matrix = new int[][]{
+                {1, 4, 7, 11, 15},
+                {2, 5, 8, 12, 19},
+                {3, 6, 9, 16, 22},
+                {10, 13, 14, 17, 24},
+                {18, 21, 23, 26, 30}
+        };
+        expected = true;
+        actual = test.searchMatrix(matrix, target);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void test2(){
+        target = 0;
+        matrix = new int[][]{};
+        expected = false;
+        actual = test.searchMatrix(matrix, target);
+        assertEquals(expected, actual);
+    }
+}