Question

您好我一直在努力让合并排序正常工作，我有一个完整的代码但是没有得到正确的结果......这是我的代码，结果是＆＃34; 876323149＆＃34;任何帮助将不胜感激。

public class MergeSort
{
  private static int[] local;  // for use in copying
  private static int[] a;
  public static void main(String[] args)
 {
  int[] test = {2,3,1,4,7,8,6,3,9};
  sort(test);}

  public static void sort(int[] orig)
  {
    int n = orig.length;
    local = new int[n];
    a = orig;
    recursiveSort(0, n-1);
    for(int i = 0; i < a.length; i ++){
    System.out.print(a[i]);
  }
  }

  private static void recursiveSort(int lo, int hi)
  {
    int mid =(hi + lo) / 2;
    if(hi-lo > 2){
      recursiveSort(lo, mid);
      recursiveSort(mid + 1, hi);
      merge(lo, mid + 1, hi);

    }      
  }

  private static void merge(int lo, int mid, int hi)
  {
    int d = lo;
    int b = mid + 1;
    int c = lo;
    for (int i = lo; i <= hi; i++) {
      local[i] = a[i];
    }
    while(d <= mid && b <= hi){
      if(local[d] > local[b]){
        a[c] = local[d];
        d++;}
      else{
        a[c] = local[b];
        b++;}
      c++;}
   while (d <= mid) {
      a[c] = local[d];
      c++;
      d++;
    }
  }
}

Answer 1

你必须确保lo小于hi，以便recursiveSort继续递归地对不同的数组进行排序，并且不会尝试对长度为＆lt; = 1的数组进行排序。更重要的是，mid必须设置在每次调用if语句时都会使用if语句

以下是修复：

private static void recursiveSort(int lo, int hi)
{
if(lo < hi){
int mid =(hi + lo) / 2;

recursiveSort(lo, mid);
recursiveSort(mid + 1, hi);
merge(lo, mid + 1, hi);

}      
}

Java Merge Sort无效

1 个答案: