feat: add Minimum Average Difference (#1171)

* add leetcode Minimum Average Difference

* updating DIRECTORY.md

Co-authored-by: David Leal <halfpacho@gmail.com>
Co-authored-by: github-actions[bot] <github-actions@users.noreply.github.com>

DIRECTORY.md

@@ -217,6 +217,7 @@
     * [217](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/217.c)
     * [2222](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/2222.c)
     * [223](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/223.c)
+    * [2256](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/2256.c)
     * [226](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/226.c)
     * [2270](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/2270.c)
     * [230](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/230.c)
@@ -271,6 +272,7 @@
     * [771](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/771.c)
     * [79](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/79.c)
     * [8](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/8.c)
+    * [807](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/807.c)
     * [82](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/82.c)
     * [83](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/83.c)
     * [852](https://github.com/TheAlgorithms/C/blob/HEAD/leetcode/src/852.c)

leetcode/DIRECTORY.md

@@ -117,5 +117,6 @@
 | 2024 | [Maximize the Confusion of an Exam](https://leetcode.com/problems/maximize-the-confusion-of-an-exam/)                           | [C](./src/2024.c) | Medium     |
 | 2130 | [Maximum Twin Sum of a Linked List](https://leetcode.com/problems/maximum-twin-sum-of-a-linked-list/)                           | [C](./src/2130.c) | Medium     |
 | 2222 | [Number of Ways to Select Buildings](https://leetcode.com/problems/number-of-ways-to-select-buildings/)                         | [C](./src/2222.c) | Medium     |
+| 2256 | [Minimum Average Difference](https://leetcode.com/problems/minimum-average-difference/)                                         | [C](./src/2256.c) | Medium     |
 | 2270 | [Number of Ways to Split Array](https://leetcode.com/problems/number-of-ways-to-split-array/)                                   | [C](./src/2270.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/2256.c

@@ -0,0 +1,37 @@
+// Prefix sum.
+// - Calculate whole nums sum.
+// - Calculate currIndex sum.
+// - Compare averages
+// Runtime: O(n)
+// Space: O(1)
+
+int minimumAverageDifference(int* nums, int numsSize){
+    long numsSum = 0;
+    for (int i = 0; i < numsSize; i++){
+        numsSum += nums[i];
+    }
+    
+    long currSum = 0;
+    long minAverage = 9223372036854775807; // Long max
+    int minIndex = 0;
+    
+    for (int i = 0; i < numsSize; i++){
+        currSum += nums[i];
+
+        int leftItemsNumber = (numsSize - i  - 1);
+        long leftItemsNumberAverage = 0;
+        if (leftItemsNumber != 0){
+            leftItemsNumberAverage = (numsSum - currSum) / leftItemsNumber;
+        }
+
+        long currItemsNumberAverage = currSum / (i + 1);
+        long averageDiff = abs(currItemsNumberAverage - leftItemsNumberAverage);
+
+        if (averageDiff < minAverage){
+            minAverage = averageDiff;
+            minIndex = i;
+        }
+    }
+
+    return minIndex;
+}