C实现 排序技术

1.交换排序 

冒泡排序 (bubble sort) 

 

#include<stdio.h>
void bubble_sort(int arr[], int len) {   
	int j,exchange,bound,temp;
	exchange = len-1;    //第一趟起泡的区间是r[0]-r[len]
	while (exchange != 0) {       //当上一趟排序有记录交换时
		bound = exchange;
		exchange = 0;
		for (j = 0; j < bound; j++) {  //区间是r[0]-r[bound]
			if (arr[j] > arr[j + 1]) {
				temp = arr[j];
				arr[j] = arr[j + 1];
				arr[j + 1] = temp;
				exchange = j;
			}
		}
	}
}
int main() {
	int arr[] = { 22, 34, 3, 32, 82, 55, 89, 50, 37, 5, 64, 35, 9, 70 };
	int len = (int) sizeof(arr) / sizeof(*arr);
	bubble_sort(arr, len);
	int i;
	for (i = 0; i < len; i++)
		printf("%d ", arr[i]);
	system("pause");
	return 0;
	
}

快速排序 (quick sort)

①迭代法

#include<stdio.h>
typedef struct _Range {
	int start, end;
} Range;
Range new_Range(int s, int e) {
	Range r;
	r.start = s;
	r.end = e;
	return r;
}
void swap(int *x, int *y) {
	int t = *x;
	*x = *y;
	*y = t;
}
void quick_sort(int arr[], const int len) {
	if (len <= 0)
		return; // 避免len等于负值时引发段错误（Segment Fault）
				// r[]模拟列表,p为数量,r[p++]为push,r[--p]为pop且取得元素
	Range r[14];
	int p = 0;
	r[p++] = new_Range(0, len - 1);
	while (p) {
		Range range = r[--p];
		if (range.start >= range.end)
			continue;
		int mid = arr[(range.start + range.end) / 2]; // 选取中间点为基准点
		int left = range.start, right = range.end;
		do
		{
			while (arr[left] < mid) ++left;   // 检测基准点左侧是否符合要求
			while (arr[right] > mid) --right; //检测基准点右侧是否符合要求

			if (left <= right)
			{
				swap(&arr[left], &arr[right]);
				left++; right--;               // 移动指针易继续
			}
		} while (left <= right);

		if (range.start < right) r[p++] = new_Range(range.start, right);
		if (range.end > left) r[p++] = new_Range(left, range.end);
	}
}
int main() {
	int arr[] = { 22, 34, 3, 32, 82, 55, 89, 50, 37, 5, 64, 35, 9, 70 };
	int len = (int) sizeof(arr) / sizeof(*arr);
	quick_sort(arr,len);
	int i;
	for (i = 0; i < len; i++)
		printf("%d ", arr[i]);
	system("pause");
	return 0;
	
}

 

②递归法

#include<stdio.h>
void swap(int *x, int *y) {
	int t = *x;
	*x = *y;
	*y = t;
}
void quick_sort_recursive(int arr[], int start, int end) {
	if (start >= end)
		return;
	int mid = arr[end];
	int left = start, right = end - 1;
	while (left < right) {
		while (arr[left] < mid && left < right)
			left++;
		while (arr[right] >= mid && left < right)
			right--;
		swap(&arr[left], &arr[right]);
	}
	if (arr[left] >= arr[end])
		swap(&arr[left], &arr[end]);
	else
		left++;
	if (left)
		quick_sort_recursive(arr, start, left - 1);
	quick_sort_recursive(arr, left + 1, end);
}
int main() {
	int arr[] = { 22, 34, 3, 32, 82, 55, 89, 50, 37, 5, 64, 35, 9, 70 };
	int len = (int) sizeof(arr) / sizeof(*arr);
	quick_sort_recursive(arr,0,len-1);
	int i;
	for (i = 0; i < len; i++)
		printf("%d ", arr[i]);
	system("pause");
	return 0;
	
}

2. 选择排序

 简单选择排序 (simple selection sort)

 

void swap(int *a, int *b) //交换两个变数
{
	int temp = *a;
	*a = *b;
	*b = temp;
}
void selection_sort(int arr[], int len)
{
	int i, j;
	for (i = 0; i < len - 1; i++)
	{
		int min = i;
		for (j = i + 1; j < len; j++)     //走访未排序的元素
			if (arr[j] < arr[min])    //找到目前最小值
				min = j;    //记录最小值
		swap(&arr[min], &arr[i]);    //做交换
	}
}

堆排序 (heap sort)

 

3.插入排序 

直接插入排序 (straight insertion sort)

 

void insertion_sort(int arr[], int len) {
	int i, j, temp;
	for (i = 1; i<len; i++) {   //第一个元素记为"已排序"
		temp = arr[i];
		for (j = i; j > 0 && arr[j - 1]>temp; j--)
			arr[j] = arr[j - 1];
		arr[j] = temp;
	}
}

 希尔排序 (shell sort缩小增量排序)----插入排序的升级版，会优先比较距离较远的元素。

void shell_sort(int arr[], int len) {
    int gap, i, j;
    int temp;
    for (gap = len >> 1; gap > 0; gap = gap >>= 1)
        for (i = gap; i < len; i++) {
            temp = arr[i];
            for (j = i - gap; j >= 0 && arr[j] > temp; j -= gap)
                arr[j + gap] = arr[j];
            arr[j + gap] = temp;
        }
}

4.归并排序

 

二路归并排序的递归实现 (Recursive implementation of two-way merge sort)

#include<stdio.h>
void merge_sort_recursive(int arr[], int reg[], int start, int end) {
	if (start >= end)
		return;
	int len = end - start, mid = (len >> 1) + start;  //相当于len除以2
	int start1 = start, end1 = mid;
	int start2 = mid + 1, end2 = end;
	merge_sort_recursive(arr, reg, start1, end1);
	merge_sort_recursive(arr, reg, start2, end2);
	int k = start;
	while (start1 <= end1 && start2 <= end2)
		reg[k++] = arr[start1] < arr[start2] ? arr[start1++] : arr[start2++];
	while (start1 <= end1)
		reg[k++] = arr[start1++];
	while (start2 <= end2)
		reg[k++] = arr[start2++];
	for (k = start; k <= end; k++)
		arr[k] = reg[k];
}
int main() {
	int arr[] = { 22, 34, 3, 32, 82, 55, 89, 50, 37, 5, 64, 35, 9, 70 };
	int reg[14];
	int len = (int) sizeof(arr) / sizeof(*arr);
	merge_sort_recursive(arr, reg, 0, len - 1);
	int i;
	for (i = 0; i < len; i++)
		printf("%d ", arr[i]);
	system("pause");
	return 0;
	
}

 迭代法 (interative)

#include<stdio.h>
int min(int x, int y) {
	return x < y ? x : y;
}
void merge_sort(int arr[], int len) {
	int* a = arr;
	int* b = (int*)malloc(len * sizeof(int));
	int seg, start;
	for (seg = 1; seg < len; seg += seg) {
		for (start = 0; start < len; start += seg + seg) {
			int low = start, mid = min(start + seg, len), high = min(start + seg + seg, len);
			int k = low;
			int start1 = low, end1 = mid;
			int start2 = mid, end2 = high;
			while (start1 < end1 && start2 < end2)
				b[k++] = a[start1] < a[start2] ? a[start1++] : a[start2++];
			while (start1 < end1)
				b[k++] = a[start1++];
			while (start2 < end2)
				b[k++] = a[start2++];
		}
		int* temp = a;
		a = b;
		b = temp;
	}
	if (a != arr) {
		int i;
		for (i = 0; i < len; i++)
			b[i] = a[i];
		b = a;
	}
	free(b);
}
int main() {
	int arr[] = { 22, 34, 3, 32, 82, 55, 89, 50, 37, 5, 64, 35, 9, 70 };
	int len = (int) sizeof(arr) / sizeof(*arr);
	merge_sort(arr,len);
	int i;
	for (i = 0; i < len; i++)
		printf("%d ", arr[i]);
	system("pause");
	return 0;
	
}