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