C++实现归并排序

Posted 2021-05-25 Wecccccccc

代码如下:

#include <iostream>
using namespace std;
void Merge(int a[], int mid, int low, int high);
void MergeSort(int a[], int low, int high)
{
	if (low < high)
	{
		int mid = (low + high) >> 1;
		MergeSort(a, low, mid);
		MergeSort(a, mid + 1, high);
		Merge(a, mid, low, high);
	}
}

void Merge(int a[], int mid, int low, int high)
{
	int i = low;
	int j = mid + 1;
	int k = 0;
	int *w = new int[high - low + 1];
	while (i <= mid && j <= high)
	{
		if (a[i] < a[j]) w[k++] = a[i++];
		else w[k++] = a[j++];
	}
	while (i <= mid) w[k++] = a[i++];
	while (j <= high) w[k++] = a[j++];

	for (int i = low, j = 0; i <= high; i++, j++) a[i] = w[j];

	delete[] w;
}

int main()
{
	int a[] = { 12,3253,2414,1233,45,45432,34,1242,1567,123,5543,242,34,123,123 };
	MergeSort(a, 0, 15 - 1);
	for (int i = 0; i < 15; i++) cout << a[i] << " ";
	cout << endl;
	return 0;
}