feat: add compliment of 10 integer (#1136)

* add complinent of 10  integer

* Update 1009.c

add new line at the end

* Rename README.md to DIRECTORY.md

change filename

* chore: apply suggestions from code review

Co-authored-by: David Leal <halfpacho@gmail.com>

leetcode/DIRECTORY.md

@@ -90,6 +90,7 @@
 | 938  | [Range Sum of BST](https://leetcode.com/problems/range-sum-of-bst/)                                                             | [C](./src/938.c)  | Easy       |
 | 965  | [Univalued Binary Tree](https://leetcode.com/problems/univalued-binary-tree/)                                                   | [C](./src/965.c)  | Easy       |
 | 977  | [Squares of a Sorted Array](https://leetcode.com/problems/squares-of-a-sorted-array/)                                           | [C](./src/977.c)  | Easy       |
+| 1009 | [Complement of Base 10 Integer](https://leetcode.com/problems/complement-of-base-10-integer/)                                   | [C](./src/1009.c) | Easy       |
 | 1089 | [Duplicate Zeros](https://leetcode.com/problems/duplicate-zeros/)                                                               | [C](./src/1089.c) | Easy       |
 | 1184 | [Distance Between Bus Stops](https://leetcode.com/problems/distance-between-bus-stops/)                                         | [C](./src/1184.c) | Easy       |
 | 1189 | [Maximum Number of Balloons](https://leetcode.com/problems/maximum-number-of-balloons/)                                         | [C](./src/1189.c) | Easy       |

leetcode/src/1009.c

@@ -0,0 +1,15 @@
+// Bit manipulation.
+// - Find the bit length of n using log2
+// - Create bit mask of bit length of n
+// - Retun ~n and bit of ones mask
+// Runtime: O(log2(n))
+// Space: O(1)
+
+int bitwiseComplement(int n){
+    if (n == 0){
+        return 1;
+    }
+
+    int binary_number_length = ceil(log2(n));
+    return (~n) & ((1 << binary_number_length) - 1);
+}