Implement merge sort in Rust

opixelum · Dec 7, 2023 · 1208a6b · 1208a6b
1 parent 7f78985
commit 1208a6b
Showing 1 changed file with 43 additions and 0 deletions.
diff --git a/rust/src/sorting.rs b/rust/src/sorting.rs
@@ -1,3 +1,5 @@
+use crate::arrays::{copy_arrays, merge_arrays};
+
 pub fn insertion_sort<T: PartialOrd + Clone>(array: &mut [T]) {
     let size = array.len();
 
@@ -81,6 +83,22 @@ pub fn cocktail_sort<T: PartialOrd + Clone>(array: &mut [T]) {
     }
 }
 
+pub fn merge_sort<T: PartialOrd + Clone>(array: &mut [T]) {
+    let len = array.len();
+    if len > 1 {
+        let middle = array.len() / 2;
+        let (left, right) = array.split_at_mut(middle);
+
+        merge_sort(left);
+        merge_sort(right);
+
+        let mut temp = vec![left[0].clone(); len];
+        merge_arrays(left, right, &mut temp);
+
+        copy_arrays(&temp, array);
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -198,4 +216,29 @@ mod tests {
             SORTED_STRING_ARRAY.iter().map(|&s| s.into()).collect();
         assert_eq!(string_array, sorted_string_array);
     }
+
+    #[test]
+    fn test_merge_sort() {
+        let mut int_array = INT_ARRAY;
+        merge_sort(&mut int_array);
+        assert_eq!(int_array, SORTED_INT_ARRAY);
+
+        let mut float_array = FLOAT_ARRAY;
+        merge_sort(&mut float_array);
+        assert_eq!(float_array, SORTED_FLOAT_ARRAY);
+
+        let mut char_array = CHAR_ARRAY;
+        merge_sort(&mut char_array);
+        assert_eq!(char_array, SORTED_CHAR_ARRAY);
+
+        let mut string_slice_array = STRING_SLICE_ARRAY;
+        merge_sort(&mut string_slice_array);
+        assert_eq!(string_slice_array, SORTED_STRING_SLICE_ARRAY);
+
+        let mut string_array: Vec<String> = STRING_ARRAY.iter().map(|&s| s.into()).collect();
+        merge_sort(&mut string_array);
+        let sorted_string_array: Vec<String> =
+            SORTED_STRING_ARRAY.iter().map(|&s| s.into()).collect();
+        assert_eq!(string_array, sorted_string_array);
+    }
 }