#704: description update

Author: vetalapo

c-sharp/Problems/binary-search/BinarySearchSolution.cs

@@ -3,10 +3,28 @@
  * Binary Search
  **
  * Given an array of integers nums which is sorted in ascending order,
- * and an integer target, write a function to search target in nums.
+ * and an integer target,
+ * write a function to search target in nums.
+ *
  * If target exists, then return its index. Otherwise, return -1.
  *
  * You must write an algorithm with O(log n) runtime complexity.
+ *
+ * Example 1:
+ *   Input: nums = [-1,0,3,5,9,12], target = 9
+ *   Output: 4
+ *   Explanation: 9 exists in nums and its index is 4
+ *
+ * Example 2:
+ *   Input: nums = [-1,0,3,5,9,12], target = 2
+ *   Output: -1
+ *   Explanation: 2 does not exist in nums so return -1
+ *
+ * Constraints:
+ *   • 1 <= nums.length <= 10^4
+ *   • -10^4 < nums[i], target < 10^4
+ *   • All the integers in nums are unique.
+ *   • nums is sorted in ascending order.
  **
  * https://leetcode.com/problems/binary-search/
 ***/