学步园

#include <stdio.h>
void mergeSort(int A[], int len);
void show(int A[], int len);
int main()
{
	int A[] = {1, 3, 2, 5, 7};
	int len = 5;
	mergeSort(A, 5);
	show(A, 5);
	return 0;
}
// A[p..q]和A[q+1..r]是已排序数组，该函数实现A[p..r]排序
void merge(int A[], int p, int q, int r)
{
	int *S = new int[r-p+1];
	int i = p;
	int j = q + 1;
	int k = 0;
	while (i <= q && j <= r)
		if (A[i] <= A[j])
			S[k++] = A[i++];
		else S[k++] = A[j++];
	while (i <= q)
		S[k++] = A[i++];
	while (j <= r)
		S[k++] = A[j++];
	for (i=0; i<k; ++i)
		A[p++] = S[i];
	delete []S;
	return ;
}
void mergeSort(int A[], int p, int r)
{
	if (r > p)
	{
		int q = (p + r) / 2;
		mergeSort(A, p, q);
		mergeSort(A, q + 1, r);
		merge(A, p, q, r);
	}
	return ;
}
void mergeSort(int A[], int len)
{
	mergeSort(A, 0, len-1);
	return ;
}
void show(int A[], int len)
{
	for (int i=0; i<len; ++i)
		printf("%d/n", A[i]);
	return ;
}