各种排序算法实现

标签：排序算法   归并排序   递归   非递归   

1. 归并排序算法：

非递归实现：

void mergeSort(vector<int> & nums, vector<int> &tmpNums, int left, int right, int end)//right为右边一段数据的开始，同时也可以用来判断左边一段数据的结束，并且左边的数组长度总是大于或等于右边数组长度
{
	int idx_left=left;
	int idx_right=right;
	int idx_total=left;
	while(idx_left<right && idx_right<=end)
	{
		if(nums[idx_left]<=nums[idx_right])
			tmpNums[idx_total++]=nums[idx_left++];
		else
			tmpNums[idx_total++]=nums[idx_right++];
	}
	while(idx_left<right)
		tmpNums[idx_total++]=nums[idx_left++];
	while(idx_right<=end)
		tmpNums[idx_total++]=nums[idx_right++];

	idx_left=left;
	while(idx_left<=end)
	{
		nums[idx_left]=tmpNums[idx_left];
		idx_left++;
	}
}

void merge(vector<int> & nums, vector<int> & tmpNums)
{
	int step=1;
	int i;
	int n=nums.size();
	while(step<n)
	{
		for(i=0; i<=n-2*step; i+=2*step)//注意，这里i<=n-2*step是因为要保证最后的一对step数组能够正确排序
		{
			mergeSort(nums, tmpNums, i, i+step, i+2*step-1);
		}
		if(i<n-step)
			mergeSort(nums, tmpNums, i, i+step, n-1);//对于最后不能正好是一对step长度的情况，要单独处理，且保证最后一个参数为n-1
		step*=2;
	}

}

void mergeSort(vector<int> & nums, vector<int> &tmpNums, int left, int right, int end)
{
	int idx_left=left;
	int idx_right=right;
	int idx_total=left;
	while(idx_left<right && idx_right<=end)
	{
		if(nums[idx_left]<=nums[idx_right])
			tmpNums[idx_total++]=nums[idx_left++];
		else
			tmpNums[idx_total++]=nums[idx_right++];
	}
	while(idx_left<right)
		tmpNums[idx_total++]=nums[idx_left++];
	while(idx_right<=end)
		tmpNums[idx_total++]=nums[idx_right++];

	idx_left=left;
	while(idx_left<=end)
	{
		nums[idx_left]=tmpNums[idx_left];
		idx_left++;
	}
}

void merge(vector<int> & nums, vector<int> & tmpNums, int left, int right)
{
	if(left<right)
	{
		int mid=(left+right)/2;
		merge(nums, tmpNums, left, mid);
		merge(nums, tmpNums, mid+1, right);
		mergeSort(nums, tmpNums, left, mid+1, right);
	}
}

各种排序算法实现

标签：排序算法   归并排序   递归   非递归   

原文地址：http://blog.csdn.net/jisuanji_wjfioj/article/details/46490373