Java排序演算法

標籤：java   排序演算法   演算法   排序   

概述：

以下是對使用Java對各種排序演算法的一個展示。

冒泡排序

public class BubbleSort {public static int[] bubbleSort(int[] array) {if (array == null) {return null;}for (int i = 0; i < array.length; i++) {for (int j = i + 1; j < array.length; j++) {if (array[i] > array[j]) {array[i] = array[i] + array[j];array[j] = array[i] - array[j];array[i] = array[i] - array[j];}}}return array;}}

插入排序

public class InsertSort {public static int[] insertSort(int[] array) {if (array == null) {return null;}for (int i = 1; i < array.length; i++) {for (int j = i; (j > 0) && (array[j] < array[j - 1]); j--) {SortUtils.swap(array, j, j - 1);}}return array;}}

選擇排序

public class SelectionSort {public static int[] selectionSort(int[] array) {if (array == null) {return null;}for (int i = 0; i < array.length; i++) {int lowIndex = i;for (int j = array.length - 1; j > i; j--) {if (array[j] < array[lowIndex]) {lowIndex = j;}}SortUtils.swap(array, i, lowIndex);}return array;}}

Shell排序

public class ShellSort {public static int[] shellSort(int[] array) {if (array == null) {return null;}for (int i = array.length / 2; i > 2; i /= 2) {for (int j = 0; j < i; j++) {insertSort(array, j, i);}}insertSort(array, 0, 1);return array;}private static void insertSort(int[] array, int start, int inc) {for (int i = start + inc; i < array.length; i += inc) {for (int j = i; (j >= inc) && (array[j] < array[j - inc]); j -= inc) {SortUtils.swap(array, j, j - inc);}}}}

快速排序

public class QKSort {public static int[] quickSort(int[] array) {if (array != null) {return quickSort(array, 0, array.length - 1);}return null;}private static int[] quickSort(int[] array, int beg, int end) {if (beg >= end || array == null) {return null;}int p = partition(array, beg, end);quickSort(array, beg, p - 1);quickSort(array, p + 1, end);return array;}/** * 找到分界點 * @param array * @param beg * @param end * @return */private static int partition(int[] array, int beg, int end) {int last = array[end];int i = beg - 1;for (int j = beg; j <= end - 1; j++) {if (array[j] <= last) {i++;if (i != j) {array[i] = array[i] ^ array[j];array[j] = array[i] ^ array[j];array[i] = array[i] ^ array[j];}}}if ((i + 1) != end) {array[i + 1] = array[i + 1] ^ array[end];array[end] = array[i + 1] ^ array[end];array[i + 1] = array[i + 1] ^ array[end];}return i + 1;}}

堆排序

public class HeapSort {public static int[] heapSort(int[] array) {if (array == null) {return null;}MaxHeap h = new MaxHeap();h.init(array);for (int i = 0; i < array.length; i++) {h.remove();}System.arraycopy(h.queue, 1, array, 0, array.length);return array;}private static class MaxHeap {void init(int[] data) {this.queue = new int[data.length + 1];for (int i = 0; i < data.length; i++) {queue[++size] = data[i];fixUp(size);}}private int size = 0;private int[] queue;public int get() {return queue[1];}public void remove() {SortUtils.swap(queue, 1, size--);fixDown(1);}// fixdownprivate void fixDown(int k) {int j;while ((j = k << 1) <= size) {if (j < size && queue[j] < queue[j + 1]) {j++;}// 不用交換if (queue[k] > queue[j]) {break;}SortUtils.swap(queue, j, k);k = j;}}private void fixUp(int k) {while (k > 1) {int j = k >> 1;if (queue[j] > queue[k]) {break;}SortUtils.swap(queue, j, k);k = j;}}}}

歸併排序

public class MergeSort {public static int[] mergeSort(int[] array) {if (array == null) {return null;}int[] temp = new int[array.length];return mergeSort(array, temp, 0, array.length - 1);}private static int[] mergeSort(int[] array, int[] temp, int l, int r) {int mid = (l + r) / 2;if (l == r) {return null;}mergeSort(array, temp, l, mid);mergeSort(array, temp, mid + 1, r);for (int i = l; i <= r; i++) {temp[i] = array[i];}int i1 = l;int i2 = mid + 1;for (int cur = l; cur <= r; cur++) {if (i1 == mid + 1) {array[cur] = temp[i2++];} else if (i2 > r) {array[cur] = temp[i1++];} else if (temp[i1] < temp[i2]) {array[cur] = temp[i1++];} else {array[cur] = temp[i2++];}}return array;}}

歸併排序(改進)

public class MergeSortImproved {private static final int THRESHOLD = 10;public static int[] mergeSort(int[] array) {if (array == null) {return null;}int[] temp = new int[array.length];return mergeSort(array, temp, 0, array.length - 1);}private static int[] mergeSort(int[] array, int[] temp, int l, int r) {int i, j, k;int mid = (l + r) / 2;if (l == r) {return null;}if ((mid - l) >= THRESHOLD) {mergeSort(array, temp, l, mid);} else {insertSort(array, l, mid - l + 1);}if ((r - mid) > THRESHOLD) {mergeSort(array, temp, mid + 1, r);} else {insertSort(array, mid + 1, r - mid);}for (i = l; i <= mid; i++) {temp[i] = array[i];}for (j = 1; j <= r - mid; j++) {temp[r - j + 1] = array[j + mid];}int a = temp[l];int b = temp[r];for (i = l, j = r, k = l; k <= r; k++) {if (a < b) {array[k] = temp[i++];a = temp[i];} else {array[k] = temp[j--];b = temp[j];}}return array;}private static void insertSort(int[] array, int start, int len) {for (int i = start + 1; i < start + len; i++) {for (int j = i; (j > start) && array[j] < array[j - 1]; j--) {SortUtils.swap(array, j, j - 1);}}}}

完整原始碼下載(包含測試案例及工具類)：

http://download.csdn.net/detail/u013761665/8698287

Java排序演算法