-
Notifications
You must be signed in to change notification settings - Fork 379
Expand file tree
/
Copy pathMergeSort.java
More file actions
60 lines (49 loc) · 1.59 KB
/
Copy pathMergeSort.java
File metadata and controls
60 lines (49 loc) · 1.59 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
// Merge Sort Algorithm in Java
// Time Complexity: O(n log n)
// A Divide and Conquer algorithm that divides the array, sorts and merges it.
public class MergeSort {
public static void sort(int[] arr) {
mergeSort(arr, 0, arr.length - 1);
}
// Recursive merge sort
private static void mergeSort(int[] arr, int left, int right) {
if (left < right) {
int mid = (left + right) / 2;
// Sort first and second halves
mergeSort(arr, left, mid);
mergeSort(arr, mid + 1, right);
// Merge the sorted halves
merge(arr, left, mid, right);
}
}
// Merge two sorted halves
private static void merge(int[] arr, int left, int mid, int right) {
int n1 = mid - left + 1;
int n2 = right - mid;
int[] L = new int[n1];
int[] R = new int[n2];
for (int i = 0; i < n1; i++)
L[i] = arr[left + i];
for (int j = 0; j < n2; j++)
R[j] = arr[mid + 1 + j];
int i = 0, j = 0, k = left;
// Merge the temp arrays back into arr
while (i < n1 && j < n2) {
if (L[i] <= R[j])
arr[k++] = L[i++];
else
arr[k++] = R[j++];
}
// Copy remaining elements of L[] or R[]
while (i < n1)
arr[k++] = L[i++];
while (j < n2)
arr[k++] = R[j++];
}
public static void main(String[] args) {
int[] data = {38, 27, 43, 3, 9, 82, 10};
sort(data);
for (int num : data)
System.out.print(num + " ");
}
}