add: Search a 2D Matrix II

Author: hijiangtao

README.md

@@ -28,6 +28,7 @@ Progress: 20/
 |196|[Delete Duplicate Emails](https://leetcode.com/problems/delete-duplicate-emails/) | [SQL](./src/delete-duplicate-emails/res.txt)|Easy|
 |197|[Rising Temperature](https://leetcode.com/problems/rising-temperature/) | [SQL](./src/rising-temperature/res.txt)|Easy|
 |206|[Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/) | [JavaScript](./src/reverse-linked-list/res.js)|Easy|
+|240|[Search a 2D Matrix II](https://leetcode.com/problems/search-a-2d-matrix-ii/) | [JavaScript](./src/search-a-2d-matrix-ii/res.js)|Medium|
 |342|[Power of Four](https://leetcode.com/problems/power-of-four/) | [JavaScript](./src/power-of-four/res.js)|Easy|
 |344|[Reverse String](https://leetcode.com/problems/reverse-string/) | [JavaScript](./src/reverse-string/res.js)|Easy|
 |404|[Sum of Left Leaves](https://leetcode.com/problems/sum-of-left-leaves/) | [JavaScript](./src/sum-of-left-leaves/res.js)|Easy|

src/search-a-2d-matrix-ii/res.js

@@ -0,0 +1,52 @@
+// 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.
+// For example,
+
+// Consider the following matrix:
+
+// [
+//   [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]
+// ]
+// Given target = 5, return true.
+
+// Given target = 20, return false.
+
+/**
+ * res.js
+ * @authors Joe Jiang (hijiangtao@gmail.com)
+ * @date    2017-02-26 22:12:39
+ * @version $Id$
+ *
+ *
+ * @param {number[][]} matrix
+ * @param {number} target
+ * @return {boolean}
+ */
+let searchMatrix = function(matrix, target) {
+    // Nothing in the matrix
+    if (matrix.length === 0 || matrix[0] === 0) {
+        return false;
+    }
+    
+    let rowlen = matrix.length,
+        collen = matrix[0].length;
+    
+    let i = 0, j = collen-1;
+    while (i>=0 && i<rowlen && j>=0 && j<collen) {
+        if (matrix[i][j] === target) {
+            return true;
+        } else if (matrix[i][j] > target) {
+            j -= 1;
+        } else {
+            i += 1;
+        }
+    }
+    
+    return false;
+};