排序算法模板（C语言版）

1.快速排序

//By LYLtim

void swap(int *a, int *b)
{
	int t = *a;
	*a = *b;
	*b = t; 
}

void QSort(int l, int r)
{
	int lp = l, rp = r, m = (l + r) >> 1;
	while (lp < rp) {
		while (a[lp] < a[m]) lp++;
		while (a[rp] > a[m]) rp--;
		if (lp <= rp)
			swap(&a[lp++], &a[rp--]);
	}
	if (l < rp) QSort(l, rp);
	if (lp < r) QSort(lp, r);
}

 C语音标准库函数qsort用法

int cmp(const void *a,const void *b) {
    return ( *(int*)a - *(int*)b );
}
qsort(a, n, sizeof(int), cmp);

详见：http://www.cplusplus.com/reference/cstdlib/qsort

 

2.归并排序

//By LYLtim

void merge(int start, int mid, int end)
{
	int	pl, pr, p = start,
		len1 = mid - start + 1,
		len2 = end - mid,
		left[len1], right[len2];
	for (pl = 0; pl < len1; pl++) left[pl] = a[start+pl];
	for (pr = 0; pr < len2; pr++) right[pr] = a[mid+1+pr];
	pl = pr = 0;
	while (pl < len1 && pr < len2)
		if (left[pl] < right[pr]) a[p++] = left[pl++];
		else a[p++] = right[pr++];
	while (pl < len1) a[p++] = left[pl++];
	while (pr < len2) a[p++] = right[pr++];
}
			
void sort(int start, int end)
{
	if (start < end) {
		int mid = (start + end) >> 1;
		sort(start, mid);
		sort(mid+1, end);
		merge(start, mid, end);
	}
}

 

3.希尔排序

//By LYLtim
void ShellSort(int a[], unsigned n)
{
	unsigned gap, i, j;
	for (gap = n >> 1; gap > 0; gap >>= 1)
		for (i = gap; i < n; i++)
			for (j = i - gap; j >= 0 && a[j] > a[j + gap]; j -= gap)
				swap(&a[j], &a[j + gap]);
}