八大排序算法的Python及C++实现

2016.5.7

一晚上学&写了冒泡和快排,其他六种留坑待更

冒泡

Python(未加flag)

def Bubble(array):
    n = len(array)
    for i in range(n-1):
        for j in range(n-1,i,-1):
            if array[j] < array[j-1]:
                array[j], array[j-1] = array[j-1], array[j]
    return

C++(加flag)

void Bubble(int *array, int n)
{
	int i, j, temp;
	bool flag;
	for(i = 0; i < n-1; i ++)
	{
		flag = false;
		for(j = n-1; j > i; j --)
		{
			if(array[j] < array[j-1])
			{
				temp = array[j];
				array[j] = array[j-1];
				array[j-1] = temp;
				flag = true;
			}
		}
		if(!flag)
			break;
	}
}

快排

python(left为基准,两指针,一从右往左,一从左往右)

def QuickSort(array,left,right):
    if left >= right:
        return array
    key = array[left]
    low, high = left, right
    while left < right:
        while left < right and array[right] >= key:
            right -= 1
        array[left] = array[right]
        while left < right and array[left] <= key:
            left += 1
        array[right] = array[left]
    array[right] = key
    QuickSort(array, low, left - 1)
    QuickSort(array, right + 1, high)
    return array

C++(基准left可改为rand,两指针i,j,从左往右)

void QuickSort(int *array, int left, int right)
{
	if(array == NULL || left < 0 || right < 0 || left >= right)
	{
		return;
	}
	const int base = array[left];
	swap(array[left], array[right]);
	
	int i;
	int j = left - 1;
	for(i = left; i < right; ++i)
	{
		if(array[i] < base)
			if(i != ++j)
				swap(array[i],array[j]);
	}
	swap(array[++ j], array[right]);
	
	QuickSort(array, left, j - 1);
	QuickSort(array, j + 1, right);	
}

void swap(int &val1, int &val2)
{
	int temp = val1;
	val1 = val2;
	val2 = temp;
}

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