added merge sort algorithm in rust

CONTRIBUTING.md

@@ -183,4 +183,5 @@ Unfortunately, sometimes the bug can be only reproduced in your project or in yo
 - [Md Azharuddin](https://github.com/azhar1038)
 - [Jatin7385](https://github.com/Jatin7385)
 - [Rhuancpq](https://github.com/Rhuancpq)
-- [Omkarnath](https://github.com/pomkarnath98)
+- [Omkarnath](https://github.com/pomkarnath98)
+- [anish](https://github.com/anishk85)

README.md

@@ -15,7 +15,7 @@ LinearSearch | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: |   | :+1: | :+1:
 InsertionSort | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: |   | :+1: | :+1: |   |   |   |   | 
 QuickSort | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: |   | :+1: | :+1: | :+1: |   |   |   |   | 
 BinarySearch | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: |   |   | :+1: |   | :+1: |   |   |   | 
-MergeSort | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: |   |   |   |   |   |   | 
+MergeSort | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: |   | :+1: |   |   |   |   | 
 GreatestCommonDivisor | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: |   | :+1: |   | :+1: |   |   |   |   |   | 
 SelectionSort | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: | :+1: |   | :+1: |   |   | :+1: |   |   |   |   | 
 Doomsday | :+1: | :+1: | :+1: | :+1: |   | :+1: | :+1: | :+1: | :+1: |   |   | :+1: |   |   |   |   |   | 

algorithms/Rust/MergeSort/merge_sort.rs

@@ -0,0 +1,86 @@
+pub struct Solution;
+
+impl Solution {
+    pub fn sort_array(nums: Vec<i32>) -> Vec<i32> {
+        let mut nums = nums;
+        if nums.len() > 1 {
+            let mid = nums.len() / 2;
+            let right = nums.split_off(mid);
+            let sorted_l = Self::sort_array(nums);
+            let sorted_r = Self::sort_array(right);
+
+            let mut res = Vec::with_capacity(sorted_l.len() + sorted_r.len());
+            let (mut i, mut j) = (0, 0);
+
+            while i < sorted_l.len() && j < sorted_r.len() {
+                if sorted_l[i] <= sorted_r[j] {
+                    res.push(sorted_l[i]);
+                    i += 1;
+                } else {
+                    res.push(sorted_r[j]);
+                    j += 1;
+                }
+            }
+            res.extend_from_slice(&sorted_l[i..]);
+            res.extend_from_slice(&sorted_r[j..]);
+            res
+        } else {
+            nums
+        }
+    }
+}
+
+fn main() {
+    // Test with integers
+    let numbers = vec![64, 34, 25, 12, 22, 11, 90];
+    println!("Original array: {:?}", numbers);
+    let sorted_numbers = Solution::sort_array(numbers);
+    println!("Sorted array: {:?}", sorted_numbers);
+
+    // Test with empty array
+    let empty: Vec<i32> = vec![];
+    println!("\nOriginal array: {:?}", empty);
+    let sorted_empty = Solution::sort_array(empty);
+    println!("Sorted array: {:?}", sorted_empty);
+
+    // Test with single element
+    let single = vec![42];
+    println!("\nOriginal array: {:?}", single);
+    let sorted_single = Solution::sort_array(single);
+    println!("Sorted array: {:?}", sorted_single);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_sort_array_integers() {
+        let arr = vec![64, 34, 25, 12, 22, 11, 90];
+        assert_eq!(Solution::sort_array(arr), vec![11, 12, 22, 25, 34, 64, 90]);
+    }
+
+    #[test]
+    fn test_sort_array_already_sorted() {
+        let arr = vec![1, 2, 3, 4, 5];
+        assert_eq!(Solution::sort_array(arr), vec![1, 2, 3, 4, 5]);
+    }
+
+    #[test]
+    fn test_sort_array_reverse_sorted() {
+        let arr = vec![5, 4, 3, 2, 1];
+        assert_eq!(Solution::sort_array(arr), vec![1, 2, 3, 4, 5]);
+    }
+
+    #[test]
+    fn test_sort_array_empty() {
+        let arr: Vec<i32> = vec![];
+        assert_eq!(Solution::sort_array(arr), vec![]);
+    }
+
+    #[test]
+    fn test_sort_array_single_element() {
+        let arr = vec![42];
+        assert_eq!(Solution::sort_array(arr), vec![42]);
+    }
+}