101 lines
2.6 KiB
Java
101 lines
2.6 KiB
Java
/**
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*
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* @author Varun Upadhyay (https://github.com/varunu28)
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*
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*/
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class MergeSort {
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/**
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* This method implements the Generic Merge Sort
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*
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* @param arr The array to be sorted
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* @param temp The copy of the actual array
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* @param left The first index of the array
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* @param right The last index of the array
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* Recursively sorts the array in increasing order
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**/
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public static <T extends Comparable<T>> void MS(T[] arr, T[] temp, int left, int right) {
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if (left < right) {
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int mid = left + (right - left) / 2;
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MS(arr, temp, left, mid);
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MS(arr, temp,mid + 1, right);
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merge(arr, temp, left, mid, right);
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}
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}
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/**
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* This method implements the merge step of the merge sort
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*
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* @param arr The array to be sorted
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* @param temp The copy of the actual array
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* @param left The first index of the array
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* @param mid The middle index of the array
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* @param right The last index of the array
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* merges two parts of an array in increasing order
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**/
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public static <T extends Comparable<T>> void merge(T[] arr, T[] temp, int left, int mid, int right) {
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for (int i=left;i<=right;i++) {
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temp[i] = arr[i];
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}
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int i= left;
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int j = mid + 1;
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int k = left;
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while (i<=mid && j<=right) {
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if (temp[i].compareTo(temp[j]) <= 0) {
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arr[k] = temp[i];
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i++;
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}
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else {
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arr[k] = temp[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 <= mid) {
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arr[k] = temp[i];
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i++;
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k++;
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}
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}
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// Driver program
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public static void main(String[] args) {
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// Integer Input
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int[] arr = {4,23,6,78,1,54,231,9,12};
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Integer[] array = new Integer[arr.length];
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for (int i=0;i<array.length;i++) {
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array[i] = arr[i];
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}
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// Copy of actual array
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Integer[] temp = new Integer[arr.length];
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MS(array, temp, 0, arr.length-1);
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// Output => 1 4 6 9 12 23 54 78 231
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for (int i=0;i<arr.length;i++) {
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System.out.print(array[i] + " ");
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}
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System.out.println();
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// String Input
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String[] array1 = {"c", "a", "e", "b","d"};
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String[] temp1 = new String[array1.length];
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MS(array1, temp1, 0, array1.length-1);
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//Output => a b c d e
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for(int i=0; i<array1.length; i++)
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{
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System.out.print(array1[i]+"\t");
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}
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}
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}
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