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MergeSort.java
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62 lines (53 loc) · 1.58 KB
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package sort;
public class MergeSort {
/**
* The method for sorting the numbers
*/
public static void mergeSort(int[] list) {
if (list.length > 1) {
// Merge sort the first half
int[] firstHalf = new int[list.length / 2];
System.arraycopy(list, 0, firstHalf, 0, list.length / 2);
mergeSort(firstHalf);
// Merge sort the second half
int secondHalfLength = list.length - list.length / 2;
int[] secondHalf = new int[secondHalfLength];
System.arraycopy(list, list.length / 2,
secondHalf, 0, secondHalfLength);
mergeSort(secondHalf);
// Merge firstHalf with secondHalf into list
merge(firstHalf, secondHalf, list);
}
}
/**
* Merge two sorted lists
*/
public static void merge(int[] list1, int[] list2, int[] temp) {
int current1 = 0; // Current index in list1
int current2 = 0; // Current index in list2
int current3 = 0; // Current index in temp
while (current1 < list1.length && current2 < list2.length) {
if (list1[current1] < list2[current2]) {
temp[current3++] = list1[current1++];
} else {
temp[current3++] = list2[current2++];
}
}
while (current1 < list1.length) {
temp[current3++] = list1[current1++];
}
while (current2 < list2.length) {
temp[current3++] = list2[current2++];
}
}
/**
* A test method
*/
public static void main(String[] args) {
int[] list = {2, 3, 2, 5, 6, 1, -2, 3, 14, 12};
mergeSort(list);
for (int i = 0; i < list.length; i++) {
System.out.print(list[i] + " ");
}
}
}