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Merge pull request TheAlgorithms#490 from lq920320/Development
add some tests for Sort
2 parents 90a4c36 + 89f1c37 commit 3eff872

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‎src/main/com/java/sorts/BubbleSort.java

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package src.main.com.java.sorts;
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import static src.main.com.java.sorts.SortUtils.less;
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import static src.main.com.java.sorts.SortUtils.swap;
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public class BubbleSort {
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/**
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* This method implements the Generic Bubble Sort
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*
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* @param array The array to be sorted
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* Sorts the array in increasing order
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**/
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public <T extends Comparable<T>> T[] sort(T[] array) {
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int last = array.length;
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//Sorting
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boolean swap;
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do {
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swap = false;
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for (int count = 0; count < last - 1; count++) {
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if (less(array[count + 1], array[count])) {
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swap = swap(array, count, count + 1);
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}
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}
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last--;
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} while (swap);
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return array;
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}
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}

‎src/main/com/java/sorts/HeapSort.java

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package src.main.com.java.sorts;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.List;
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import static src.main.com.java.sorts.SortUtils.less;
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import static src.main.com.java.sorts.SortUtils.swap;
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public class HeapSort {
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private static class Heap<T extends Comparable<T>> {
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/**
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* Array to store heap
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*/
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private T[] heap;
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/**
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* Constructor
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*
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* @param heap array of unordered integers
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*/
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Heap(T[] heap) {
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this.heap = heap;
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}
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/**
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* Heapifies subtree from top as root to last as last child
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*
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* @param rootIndex index of root
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* @param lastChild index of last child
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*/
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private void heapSubtree(int rootIndex, int lastChild) {
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int leftIndex = rootIndex * 2 + 1;
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int rightIndex = rootIndex * 2 + 2;
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T root = heap[rootIndex];
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if (rightIndex <= lastChild) {
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// if has right and left children
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T left = heap[leftIndex];
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T right = heap[rightIndex];
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if (less(left, right) && less(left, root)) {
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swap(heap, leftIndex, rootIndex);
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heapSubtree(leftIndex, lastChild);
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} else if (less(right, root)) {
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swap(heap, rightIndex, rootIndex);
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heapSubtree(rightIndex, lastChild);
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}
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} else if (leftIndex <= lastChild) {
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// if no right child, but has left child
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T left = heap[leftIndex];
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if (less(left, root)) {
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swap(heap, leftIndex, rootIndex);
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heapSubtree(leftIndex, lastChild);
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}
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}
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}
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/**
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* Makes heap with root as root
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*
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* @param root index of root of heap
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*/
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private void makeMinHeap(int root) {
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int leftIndex = root * 2 + 1;
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int rightIndex = root * 2 + 2;
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boolean hasLeftChild = leftIndex < heap.length;
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boolean hasRightChild = rightIndex < heap.length;
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if (hasRightChild) {
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//if has left and right
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makeMinHeap(leftIndex);
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makeMinHeap(rightIndex);
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heapSubtree(root, heap.length - 1);
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} else if (hasLeftChild) {
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heapSubtree(root, heap.length - 1);
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}
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}
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/**
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* Gets the root of heap
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*
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* @return root of heap
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*/
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private T getRoot(int size) {
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swap(heap, 0, size);
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heapSubtree(0, size - 1);
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// return old root
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return heap[size];
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}
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}
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public <T extends Comparable<T>> T[] sort(T[] unsorted) {
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return sort(Arrays.asList(unsorted)).toArray(unsorted);
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}
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private <T extends Comparable<T>> List<T> sort(List<T> unsorted) {
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int size = unsorted.size();
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@SuppressWarnings("unchecked")
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Heap<T> heap = new Heap<>(unsorted.toArray((T[]) new Comparable[unsorted.size()]));
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// make min heap using index 0 as root.
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heap.makeMinHeap(0);
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List<T> sorted = new ArrayList<>(size);
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while (size > 0) {
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T min = heap.getRoot(--size);
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sorted.add(min);
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}
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return sorted;
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}
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}

‎src/main/com/java/sorts/QuickSort.java

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package src.main.com.java.sorts;
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import static src.main.com.java.sorts.SortUtils.less;
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import static src.main.com.java.sorts.SortUtils.swap;
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public class QuickSort {
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/**
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* This method implements the Generic Quick Sort
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*
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* @param array The array to be sorted
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* Sorts the array in increasing order
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**/
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public <T extends Comparable<T>> T[] sort(T[] array) {
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doSort(array, 0, array.length - 1);
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return array;
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}
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/**
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* The sorting process
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*
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* @param left The first index of an array
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* @param right The last index of an array
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* @param array The array to be sorted
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**/
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private static <T extends Comparable<T>> void doSort(T[] array, int left, int right) {
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if (left < right) {
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int pivot = partition(array, left, right);
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doSort(array, left, pivot - 1);
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doSort(array, pivot, right);
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}
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}
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/**
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* This method finds the partition index for an array
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*
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* @param array The array to be sorted
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* @param left The first index of an array
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* @param right The last index of an array
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* Finds the partition index of an array
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**/
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private static <T extends Comparable<T>> int partition(T[] array, int left, int right) {
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int mid = (left + right) / 2;
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T pivot = array[mid];
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while (left <= right) {
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while (less(array[left], pivot)) {
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++left;
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}
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while (less(pivot, array[right])) {
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--right;
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}
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if (left <= right) {
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swap(array, left, right);
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++left;
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--right;
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}
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}
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return left;
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}
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}

‎src/main/com/java/sorts/SelectionSort.java

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package src.main.com.java.sorts;
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import static src.main.com.java.sorts.SortUtils.less;
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import static src.main.com.java.sorts.SortUtils.swap;
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public class SelectionSort {
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/**
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* This method implements the Generic Selection Sort
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*
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* @param arr The array to be sorted
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* Sorts the array in increasing order
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**/
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public <T extends Comparable<T>> T[] sort(T[] arr) {
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int n = arr.length;
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for (int i = 0; i < n - 1; i++) {
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// Initial index of min
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int min = i;
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for (int j = i + 1; j < n; j++) {
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if (less(arr[j], arr[min])) {
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min = j;
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}
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}
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// Swapping if index of min is changed
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if (min != i) {
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swap(arr, i, min);
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}
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}
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return arr;
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}
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}

‎src/main/com/java/sorts/ShellSort.java

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package src.main.com.java.sorts;
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import static src.main.com.java.sorts.SortUtils.less;
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import static src.main.com.java.sorts.SortUtils.swap;
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public class ShellSort {
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/**
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* This method implements Generic Shell Sort.
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*
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* @param array The array to be sorted
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*/
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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 n = 1;
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while (n < length / 3) {
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n = 3 * n + 1;
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}
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while (n >= 1) {
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for (int i = n; i < length; i++) {
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for (int j = i; j >= n && less(array[j], array[j - n]); j -= n) {
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swap(array, j, j - n);
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}
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}
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n /= 3;
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}
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return array;
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}
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}

‎src/main/com/java/sorts/SortUtils.java

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package src.main.com.java.sorts;
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final class SortUtils {
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/**
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* Helper method for swapping places in array
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*
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* @param array The array which elements we want to swap
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* @param idx index of the first element
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* @param idy index of the second element
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*/
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static <T> boolean swap(T[] array, int idx, int idy) {
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T swap = array[idx];
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array[idx] = array[idy];
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array[idy] = swap;
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return true;
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}
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/**
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* This method checks if first element is less then the other element
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*
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* @param v first element
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* @param w second element
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* @return true if the first element is less then the second element
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*/
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static <T extends Comparable<T>> boolean less(T v, T w) {
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return v.compareTo(w) < 0;
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}
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/**
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* Swaps all position from {@param left} to @{@param right} for {@param array}
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*
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* @param array is an array
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* @param left is a left flip border of the array
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* @param right is a right flip border of the array
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*/
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static <T extends Comparable<T>> void flip(T[] array, int left, int right) {
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while (left <= right) {
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swap(array, left++, right--);
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}
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}
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}

‎src/test/com/java/sorts/BubbleSortTest.java

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package src.test.com.java.sorts;
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import org.junit.Assert;
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import org.junit.Test;
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import src.main.com.java.sorts.BubbleSort;
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import java.util.Arrays;
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public class BubbleSortTest {
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@Test
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public void bubbleSortTest() {
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BubbleSort bubbleSort = new BubbleSort();
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Integer[] unsortedInt = new Integer[]{0, 5, 9, 2, 1, 3, 4, 8, 6, 7};
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Integer[] sortedInt = new Integer[]{0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
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System.out.println(Arrays.toString(bubbleSort.sort(unsortedInt)));
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Assert.assertArrayEquals(sortedInt, bubbleSort.sort(unsortedInt));
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Character[] unsortedChar = new Character[]{'f', 'h', 'c', 'a', 'b', 'd', 'g', 'e'};
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Character[] sortedChar = new Character[]{'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'};
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System.out.println(Arrays.toString(bubbleSort.sort(unsortedChar)));
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Assert.assertArrayEquals(sortedChar, bubbleSort.sort(unsortedChar));
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}
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}

‎src/test/com/java/sorts/HeapSortTest.java

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package src.test.com.java.sorts;
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import org.junit.Assert;
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import org.junit.Test;
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import src.main.com.java.sorts.HeapSort;
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import java.util.Arrays;
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public class HeapSortTest {
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@Test
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public void heapSortTest() {
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HeapSort heapSort = new HeapSort();
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Integer[] unsortedInt = new Integer[]{0, 5, 9, 2, 1, 3, 4, 8, 6, 7};
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Integer[] sortedInt = new Integer[]{0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
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System.out.println(Arrays.toString(heapSort.sort(unsortedInt)));
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Assert.assertArrayEquals(sortedInt, heapSort.sort(unsortedInt));
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Character[] unsortedChar = new Character[]{'f', 'h', 'c', 'a', 'b', 'd', 'g', 'e'};
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Character[] sortedChar = new Character[]{'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'};
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System.out.println(Arrays.toString(heapSort.sort(unsortedChar)));
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Assert.assertArrayEquals(sortedChar, heapSort.sort(unsortedChar));
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}
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}

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