feat: add Minimum Deletions LeetCode problem (#1138)

* add Minimum Deletions to Make String Balanced

* Update 1653.c

add new line at the end

* Rename README.md to DIRECTORY.md

* chore: apply suggestions from code review

* Update leetcode/src/1653.c

Co-authored-by: Taj <tjgurwara99@users.noreply.github.com>

* Update leetcode/src/1653.c

Co-authored-by: Taj <tjgurwara99@users.noreply.github.com>

* Update leetcode/src/1653.c

Co-authored-by: Taj <tjgurwara99@users.noreply.github.com>

* Update 1653.c

remove redundant define

* Update leetcode/src/1653.c

Co-authored-by: John Law <johnlaw.po@gmail.com>

Co-authored-by: David Leal <halfpacho@gmail.com>
Co-authored-by: Taj <tjgurwara99@users.noreply.github.com>
Co-authored-by: John Law <johnlaw.po@gmail.com>

leetcode/DIRECTORY.md

@@ -100,6 +100,7 @@
 | 1189 | [Maximum Number of Balloons](https://leetcode.com/problems/maximum-number-of-balloons/)                                         | [C](./src/1189.c) | Easy       |
 | 1207 | [Unique Number of Occurrences](https://leetcode.com/problems/unique-number-of-occurrences/)                                     | [C](./src/1207.c) | Easy       |
 | 1524 | [Number of Sub-arrays With Odd Sum](https://leetcode.com/problems/number-of-sub-arrays-with-odd-sum/)                           | [C](./src/1524.c) | Medium     |
+| 1653 | [Minimum Deletions to Make String Balanced](https://leetcode.com/problems/minimum-deletions-to-make-string-balanced/)           | [C](./src/1653.c) | Medium     |
 | 1752 | [Check if Array Is Sorted and Rotated](https://leetcode.com/problems/check-if-array-is-sorted-and-rotated/)                     | [C](./src/1752.c) | Easy       |
 | 2130 | [Maximum Twin Sum of a Linked List](https://leetcode.com/problems/maximum-twin-sum-of-a-linked-list/)                           | [C](./src/2130.c) | Medium     |
 | 2304 | [Minimum Path Cost in a Grid](https://leetcode.com/problems/minimum-path-cost-in-a-grid/)                                       | [C](./src/2304.c) | Medium     |

leetcode/src/1653.c

@@ -0,0 +1,29 @@
+#define min(X, Y)  ((X) < (Y) ? (X) : (Y))
+
+// Dynamic programming approach. Down -> Up.
+// Runtime: O(n)
+// Space: O(1)
+int minimumDeletions(char * s){
+    int len = strlen(s);
+    
+    int aStateValue = s[0] == 'b';
+
+    int bStateValue = 0;
+    
+    int newAStateValue;
+    int newBStateValue;
+
+    for(int i = 1; i < len; i++){
+        newAStateValue = aStateValue + (s[i] == 'b');
+
+        newBStateValue = min(
+                               aStateValue,
+                               bStateValue + (s[i] == 'a')
+                             );
+            
+        aStateValue = newAStateValue;
+        bStateValue = newBStateValue;
+    }
+    
+    return min(aStateValue, bStateValue);
+}