java 基本算法之归并排序实例代码

public class MergeSort {  /**   *    *   *   * @param args   */  public static void main(String[] args) {    int a[] = { 49, 38, 65, 97, 76, 13, 27, 49, 78, 34, 12, 64, 5, 4, 62,        99, 98, 54, 56, 17, 18, 23, 34, 15, 35, 25, 53, 51 };    sort(a, 0, a.length - 1);    System.out.println(Arrays.toString(a));  }  public static void sort(int[] data, int left, int right) {    if (left < right) {      // 找出中间索引      int center = (left + right) / 2;      // 对左边数组进行递归      sort(data, left, center);      // 对右边数组进行递归      sort(data, center + 1, right);      // 合并      merge(data, left, center, right);    }  }  public static void merge(int[] data, int left, int center, int right) {    int[] tmpArr = new int[data.length];    int mid = center + 1;    // third记录中间数组的索引    int third = left;    int tmp = left;    while (left <= center && mid <= right) {      // 从两个数组中取出最小的放入中间数组      if (data[left] <= data[mid]) {        tmpArr[third++] = data[left++];      } else {        tmpArr[third++] = data[mid++];      }    }    // 剩余部分依次放入中间数组    while (left <= center) {      tmpArr[third++] = data[left++];    }    while (mid <= right) {      tmpArr[third++] = data[mid++];    }    // 将中间数组中的内容复制回原数组    while (tmp <= right) {      data[tmp] = tmpArr[tmp++];    }    System.out.println(Arrays.toString(data));  }}