Java排序五：归并排序

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public class TestDemo {public static void main(String[] args) {int[] arr = new int[10];Random random = new Random();for (int i = 0; i < arr.length; i++) {arr[i] = random.nextInt(100);}display(arr);sort(arr, 0, arr.length - 1);display(arr);}public static void sort(int[] arr, int left, int right) {if (left >= right)return;int middle = (left + right) >> 0x1;sort(arr, left, middle);sort(arr, middle + 1, right);merge(arr, left, middle, right);}private static void merge(int[] arr, int left, int middle, int right) {int[] tmpArr = new int[arr.length];int tmpIndex, startIndex;tmpIndex = startIndex = left;int secLeft = middle + 1;while (left <= middle && secLeft <= right) {if (arr[left] <= arr[secLeft]) {tmpArr[tmpIndex++] = arr[left++];} else {tmpArr[tmpIndex++] = arr[secLeft++];}}while (left <= middle) {tmpArr[tmpIndex++] = arr[left++];}while (secLeft <= right) {tmpArr[tmpIndex++] = arr[secLeft++];}System.arraycopy(tmpArr, startIndex, arr, startIndex, right - startIndex + 1);}private static void swap(int[] arr, int i, int j) {if (i == j) {return;}arr[i] = arr[i] ^ arr[j];arr[j] = arr[i] ^ arr[j];arr[i] = arr[i] ^ arr[j];}private static void display(int[] arr) {for (int i = 0, len = arr.length; i < len; i++) {System.out.print(arr[i] + "  ");}System.out.println();}}
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