【数据结构与算法】数据结构初阶：详解排序（四）——非比较排序：计数排序（鸽巢原理）——对哈希直接定址法的变形应用，排序算法复杂度及稳定性分析

//测试排序的性能对比  
void TestOP()
{
	srand(time(0));
	const int N = 100000;
	int* a1 = (int*)malloc(sizeof(int) * N);
	int* a2 = (int*)malloc(sizeof(int) * N);
	int* a3 = (int*)malloc(sizeof(int) * N);
	int* a4 = (int*)malloc(sizeof(int) * N);
	int* a5 = (int*)malloc(sizeof(int) * N);
	int* a6 = (int*)malloc(sizeof(int) * N);
	int* a7 = (int*)malloc(sizeof(int) * N);
	for (int i = 0; i < N; ++i)
	{
		a1[i] = rand();
		a2[i] = a1[i];
		a3[i] = a1[i];
		a4[i] = a1[i];
		a5[i] = a1[i];
		a6[i] = a1[i];
		a7[i] = a1[i];
	}
	//begin和end的时间差就是
	int begin1 = clock();
	InsertSort(a1, N);
	int end1 = clock();

	int begin2 = clock();
	ShellSort(a2, N);
	int end2 = clock();

	int begin3 = clock();
	SelectSort(a3, N);
	int end3 = clock();

	int begin4 = clock();
	HeapSort(a4, N);
	int end4 = clock();

	int begin5 = clock();
	QuickSort(a5, 0, N - 1);
	int end5 = clock();

	int begin6 = clock();
	MergeSort(a6, N);
	int end6 = clock();

	int begin7 = clock();
	BubbleSort(a7, N);
	int end7 = clock();

	printf("InsertSort:%d\n", end1 - begin1);
	printf("ShellSort:%d\n", end2 - begin2);
	printf("SelectSort:%d\n", end3 - begin3);
	printf("HeapSort:%d\n", end4 - begin4);
	printf("QuickSort:%d\n", end5 - begin5);
	printf("MergeSort:%d\n", end6 - begin6);
	printf("BubbleSort:%d\n", end7 - begin7);

	free(a1);
	free(a2);
	free(a3);
	free(a4);
	free(a5);
	free(a6);
	free(a7);
}

//非比较排序——计数排序
void CountSort(int* arr, int n)
{
	//找min max
	int min = arr[0], max = arr[0];
	for (int i = 1; i < n; i++)
	{
		if (arr[i] < min)
		{
			min = arr[i];
		}
		if (arr[i] > max)
		{
			max = arr[i];
		}
	}
	//确定count数组的大小 max-min+1
	int range = max - min + 1;
	int* count = (int*)malloc(sizeof(int) * (range));
	if (count == NULL)
	{
		perror("malloc fail");
		exit(1);
	}
	//对count初始化：calloc memset
	memset(count, 0, sizeof(int) * (range));
	for (int i = 0; i < n; i++)
	{
		count[arr[i] - min]++;
	}
	//将count数组中的数据还原到原数组中
	int index = 0;
	for (int i = 0; i < range; i++)
	{
		while (count[i]--)
		{
			arr[index++] = i + min;
		}
	}
}