private static void quickSortWithCocktailAndPartition(int low, int high, int[] data)
{
if (high - low < 9)
{
InsertSort.Sort(data, low, high);
return;
}
int midValue = selectPivotMidOfNine(low, high, data);
int a = low, b = a, c = high, d = c;
while (b < c)
{
while (b < c && midValue <= data[c])
{
if (midValue == data[c])
{
Util.swap(c, d--, data);
}
c--;
}
while (b < c && data[b] <= midValue)
{
if (midValue == data[b])
{
Util.swap(a++, b, data);
}
b++;
}
Util.swap(b++, c--, data);
}
int step;
// 合并
step = Math.Min(a - low, b - a);
vecswap(low, b - step, step, data);
step = Math.Min(high - d, d - c);
vecswap(b + 1, high - step + 1, step, data);
if (b - a > 1)
{
quickSortWithCocktailAndPartition(low, low + b - a - 1, data);
}
if (d - c > 1)
{
quickSortWithCocktailAndPartition(high - (d - c) + 1, high, data);
}
}
private static List <int> MergeSortOnlyList(List <int> data, int low, int high)
{
if (high - low < 15)
{
// 长度小于15则使用直接插入排序，效率可提高35%
List <int> insertList = data.GetRange(low, high - low + 1);
InsertSort.Sort(insertList, 0, insertList.Count - 1);
return(insertList);
}
List <int> mergeList = new List <int>();
int middle = (low + high) / 2;
List <int> leftMerge = MergeSortOnlyList(data, low, middle);
List <int> rightMerge = MergeSortOnlyList(data, middle + 1, high);
// 当两个子数组已经有序，直接合并
if (leftMerge[leftMerge.Count - 1] <= rightMerge[0])
{
mergeList = leftMerge;
mergeList.AddRange(rightMerge.GetRange(0, rightMerge.Count));
return(mergeList);
}
int i = 0, j = 0;
while (true)
{
if (leftMerge[i] < rightMerge[j])
{
mergeList.Add(leftMerge[i]);
if (++i == leftMerge.Count)
{
mergeList.AddRange(rightMerge.GetRange(j, rightMerge.Count - j));
break;
}
}
else
{
mergeList.Add(rightMerge[j]);
if (++j == rightMerge.Count)
{
mergeList.AddRange(leftMerge.GetRange(i, leftMerge.Count - i));
break;
}
}
}
return(mergeList);
}
private static void quickSort(int low, int high, int[] data)
{
if (low < high)
{
if (high - low < 9)
{
InsertSort.Sort(data, low, high);
return;
}
else
{
int middle = getPivotCocktail(low, high, data);
quickSort(low, middle - 1, data);
quickSort(middle + 1, high, data);
}
}
}