public class MergeSort {/*** @param arr   待排序的数组* @param left  本次归并的左边界* @param mid   本次归并的中间位置，也就是分界线* @param right 本次归并的右边界* @param <T>   泛型* @local aux   辅助空间(Auxiliary Space)*/private static <T extends Comparable<? super T>> void merge(T[] arr, int left, int mid, int right) {T[] aux = java.util.Arrays.copyOfRange(arr, left, right + 1);int i = left;int j = mid + 1;for (int t = left; t <= right; t++) {if (i > mid) {arr[t] = aux[j++ - left];} else if (j > right) {arr[t] = aux[i++ - left];} else if (aux[i - left].compareTo(aux[j - left]) < 0) {arr[t] = aux[i++ - left];} else {arr[t] = aux[j++ - left];}}}public static <T extends Comparable<? super T>> void sort(T[] arr, int left, int right) {int n = arr.length;for (int size = 1; size < n; size *= 2) {for (int i = 0; i < n - size; i += size * 2) {merge(arr, i, i + size - 1, Math.min(i + 2 * size - 1, n - 1));}}}public static <T extends Comparable<? super T>> void sort(T[] arr) {sort(arr, 0, arr.length - 1);}private static void printArr(Object[] arr) {for (Object o : arr) {System.out.print(o);System.out.print("\t");}System.out.println();}public static void main(String args[]) {Integer[] arr = {3, 5, 1, 7, 2, 9, 8, 0, 4, 6};printArr(arr);//3   5   1   7   2   9   8   0   4   6sort(arr);printArr(arr);//0   1   2   3   4   5   6   7   8   9}
}

public class MergeSort {/*** @param arr   待排序的数组* @param left  本次归并的左边界* @param mid   本次归并的中间位置，也就是分界线* @param right 本次归并的右边界* @param <T>   泛型* @local aux   辅助空间(Auxiliary Space)*/private static <T extends Comparable<? super T>> void merge(T[] arr, int left, int mid, int right) {T[] aux = java.util.Arrays.copyOfRange(arr, left, right + 1);int i = left;int j = mid + 1;for (int t = left; t <= right; t++) {if (i > mid) {arr[t] = aux[j++ - left];} else if (j > right) {arr[t] = aux[i++ - left];} else if (aux[i - left].compareTo(aux[j - left]) < 0) {arr[t] = aux[i++ - left];} else {arr[t] = aux[j++ - left];}}}public static <T extends Comparable<? super T>> void sort(T[] arr, int left, int right) {int n = arr.length;for (int size = 1; size < n; size *= 2) {for (int i = 0; i < n - size; i += size * 2) {if (arr[i + size - 1].compareTo(arr[i + size]) > 0) {merge(arr, i, i + size - 1, Math.min(i + 2 * size - 1, n - 1));}}}}public static <T extends Comparable<? super T>> void sort(T[] arr) {sort(arr, 0, arr.length - 1);}private static void printArr(Object[] arr) {for (Object o : arr) {System.out.print(o);System.out.print("\t");}System.out.println();}public static void main(String args[]) {Integer[] arr = {3, 5, 1, 7, 2, 9, 8, 0, 4, 6};printArr(arr);//3   5   1   7   2   9   8   0   4   6sort(arr);printArr(arr);//0   1   2   3   4   5   6   7   8   9}
}

public class MergeSort {/*** @param arr   待排序的数组* @param left  本次归并的左边界* @param mid   本次归并的中间位置，也就是分界线* @param right 本次归并的右边界* @param <T>   泛型* @local aux   辅助空间(Auxiliary Space)*/private static <T extends Comparable<? super T>> void merge(T[] arr, int left, int mid, int right) {T[] aux = java.util.Arrays.copyOfRange(arr, left, right + 1);int i = left;int j = mid + 1;for (int t = left; t <= right; t++) {if (i > mid) {arr[t] = aux[j++ - left];} else if (j > right) {arr[t] = aux[i++ - left];} else if (aux[i - left].compareTo(aux[j - left]) < 0) {arr[t] = aux[i++ - left];} else {arr[t] = aux[j++ - left];}}}private static <T extends Comparable<? super T>> void insertionSort(T[] arr, int left, int right) {for (int i = left + 1; i <= right; i++) {T temp = arr[i];int j = i - 1;while (j >= left && temp.compareTo(arr[j]) < 0) {arr[j + 1] = arr[j];j--;}arr[j + 1] = temp;}}public static <T extends Comparable<? super T>> void sort(T[] arr, int left, int right) {int len = arr.length;int smallSize = 4;//当规模小于4时采用插入排序for (int i = 0; i < len; i += smallSize) {insertionSort(arr, i, Math.min(i + smallSize - 1, len - 1));}for (int size = smallSize; size < len; size *= 2) {for (int i = 0; i < len - size; i += size * 2) {if (arr[i + size - 1].compareTo(arr[i + size]) > 0){merge(arr, i, i + size - 1, Math.min(i + 2 * size - 1, len - 1));}}}}public static <T extends Comparable<? super T>> void sort(T[] arr) {sort(arr, 0, arr.length - 1);}private static void printArr(Object[] arr) {for (Object o : arr) {System.out.print(o);System.out.print("\t");}System.out.println();}public static void main(String args[]) {Integer[] arr = {3, 5, 1, 7, 2, 9, 8, 0, 4, 6};printArr(arr);//3   5   1   7   2   9   8   0   4   6sort(arr);printArr(arr);//0   1   2   3   4   5   6   7   8   9}
}