49 lines
1.1 KiB
Java
49 lines
1.1 KiB
Java
package Sorts;
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import static Sorts.SortUtils.*;
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public class ShellSort implements SortAlgorithm {
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/**
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* Implements generic shell sort.
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*
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* @param array the array to be sorted.
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* @param <T> the type of elements in the array.
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* @return the sorted array.
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*/
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@Override
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public <T extends Comparable<T>> T[] sort(T[] array) {
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int length = array.length;
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int gap = 1;
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/* Calculate gap for optimization purpose */
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while (gap < length / 3) {
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gap = 3 * gap + 1;
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}
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for (; gap > 0; gap /= 3) {
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for (int i = gap; i < length; i++) {
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int j;
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T temp = array[i];
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for (j = i; j >= gap && less(temp, array[j - gap]); j -= gap) {
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array[j] = array[j - gap];
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}
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array[j] = temp;
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}
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}
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return array;
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}
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/* Driver Code */
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public static void main(String[] args) {
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Integer[] toSort = {4, 23, 6, 78, 1, 54, 231, 9, 12};
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ShellSort sort = new ShellSort();
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sort.sort(toSort);
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for (int i = 0; i < toSort.length - 1; ++i) {
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assert toSort[i] <= toSort[i + 1];
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}
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print(toSort);
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}
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}
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