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109 lines (102 loc) · 3.03 KB
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import java.util.Scanner;
/**
* This class implements MergeSort
* @author Unknown
*
*/
public class MergeSort {
/** Array for mergeSort*/
private int[] array;
/** Temp Merge Array*/
private int[] tempMergArr;
/** Length of the array*/
private int length;
/**
* Sorts inputArr with merge sort algorithm
*
* @param inputArr Array to be sorted
*/
public final void sort(int inputArr[]) {
this.array = inputArr;
this.length = inputArr.length;
this.tempMergArr = new int[this.length];
this.mergeSort(0, this.length - 1);
}
/**
* Partitions Array into recursively smaller pieces
*
* @param lowerIndex lower bound to include in the first partition
* @param higherIndex upper bound to include in the third partition
*/
private void mergeSort(int lowerIndex, int higherIndex) {
if (lowerIndex < higherIndex) {
int middle = lowerIndex + (higherIndex - lowerIndex) / 2;
// Below step sorts the left side of the array
this.mergeSort(lowerIndex, middle);
// Below step sorts the right side of the array
this.mergeSort(middle + 1, higherIndex);
// Now merge both sides
this.mergeParts(lowerIndex, middle, higherIndex);
}
}
/**
* Merges partitions
*
* @param lowerIndex The lower index
* @param middle The middle index
* @param higherIndex The higher index
*/
private void mergeParts(int lowerIndex, int middle, int higherIndex) {
for (int i = lowerIndex; i <= higherIndex; i++) {
this.tempMergArr[i] = this.array[i];
}
int i = lowerIndex;
int j = middle + 1;
int k = lowerIndex;
while (i <= middle && j <= higherIndex) {
if (this.tempMergArr[i] <= this.tempMergArr[j]) {
this.array[k] = this.tempMergArr[i];
i++;
} else {
this.array[k] = this.tempMergArr[j];
j++;
}
k++;
}
while (i <= middle) {
this.array[k] = this.tempMergArr[i];
k++;
i++;
}
}
/**
* Gets input to sort
*
* @return unsorted array of integers to sort
*/
public static int[] getInput() {
final int numElements = 6;
int[] unsorted = new int[numElements];
Scanner input = new Scanner(System.in);
System.out.println("Enter any 6 Numbers for Unsorted Array : ");
for (int i = 0; i < numElements; i++) {
unsorted[i] = input.nextInt();
}
input.close();
return unsorted;
}
/**
* Main Method
*
* @param args Command line arguments
*/
public static void main(String args[]) {
int[] inputArr = getInput();
MergeSort mergeSort = new MergeSort();
mergeSort.sort(inputArr);
for (int i : inputArr) {
System.out.print(i);
System.out.print(" ");
}
}
}