C语言强化——排序

1、完成堆排，对比堆排和qsort在排序1亿数的时间差异

#include<stdio.h>
#include<time.h>
#include<stdlib.h>
#define N 100000000
#define SWAP(a,b) {int tmp=a; a=b; b=tmp;}

//单次调整
void adjustMaxHeap(int *arr, int adjustPos, int arrlen) {
	int parent = adjustPos;
	int child = 2 * parent + 1;
	while (child < arrlen) {
		if (child + 1 < arrlen && arr[child + 1] > arr[child]) {
			child++;
		}
		if (arr[child] > arr[parent]) {
			SWAP(arr[parent], arr[child]);
			parent = child;
			child = parent * 2 + 1;
		}
		else {
			break;
		}
	}
}

void HeapSort(int *arr) {
	int i;
	for (int i = N / 2 - 1;i >= 0;i--) {
		adjustMaxHeap(arr, i, N);
	}
	SWAP(arr[0], arr[N - 1]);
	for (int i = N - 1;i > 1;i--) {
		adjustMaxHeap(arr, 0, i);
		SWAP(arr[0], arr[i - 1]);
	}
}

void printArray(int *a) {
	for (int i = 0;i < N;i++) {
		printf("%3d ", a[i]);
	}
	printf("\n");
}

void compare(const void * a, const void * b) {
	int *p1 = (int*)a;
	int *p2 = (int*)b;
	return *p1 - *p2;
}

int main() {
	int i;
	time_t start, end;
	int *a = (int*)calloc(N, sizeof(int));
	srand(time(NULL));
	for (i = 0;i < N;++i) {
		a[i] = rand() % 100;
	}
	//printArray(a, N);
	start = time(NULL);
	//HeapSort(a);
	qsort(a, N, sizeof(int), compare);
	end = time(NULL);
	//printArray(a);
	printf("use time = %d\n", end - start);
	return 0;
}

堆排时间：

qsort()时间：

2、完成计数排序，对比计数排序和堆排在排序1亿数的时间差异

#include<stdio.h>
#include<time.h>
#include<stdlib.h>
#define N 100000000
#define SWAP(a,b) {int tmp=a; a=b; b=tmp;}
#define R 100

//单次调整
void adjustMaxHeap(int *arr, int adjustPos, int arrlen) {
	int parent = adjustPos;
	int child = 2 * parent + 1;
	while (child < arrlen) {
		if (child + 1 < arrlen && arr[child + 1] > arr[child]) {
			child++;
		}
		if (arr[child] > arr[parent]) {
			SWAP(arr[parent], arr[child]);
			parent = child;
			child = parent * 2 + 1;
		}
		else {
			break;
		}
	}
}

void HeapSort(int *arr) {
	int i;
	for (int i = N / 2 - 1;i >= 0;i--) {
		adjustMaxHeap(arr, i, N);
	}
	SWAP(arr[0], arr[N - 1]);
	for (int i = N - 1;i > 1;i--) {
		adjustMaxHeap(arr, 0, i);
		SWAP(arr[0], arr[i - 1]);
	}
}

void printArray(int *a) {
	for (int i = 0;i < N;i++) {
		printf("%3d ", a[i]);
	}
	printf("\n");
}

void compare(const void * a, const void * b) {
	int *p1 = (int*)a;
	int *p2 = (int*)b;
	return *p1 - *p2;
}

void CountSort(int *arr) {
	int *count = (int*)calloc(R, sizeof(int));
	int i, j, k;
	for (i = 0;i < N;i++) {
		count[arr[i]]++;
	}
	k = 0;
	for (i = 0;i < R;i++) {
		for (j = 0;j < count[i];j++) {
			arr[k] = i;
			k++;
		}
	}
}

int main() {
	int i;
	time_t start, end;
	int *a = (int*)calloc(N, sizeof(int));
	srand(time(NULL));
	for (i = 0;i < N;++i) {
		a[i] = rand() % 100;
	}
	//printArray(a, N);
	start = time(NULL);
	//HeapSort(a);
	//qsort(a, N, sizeof(int), compare);
	CountSort(a);
	end = time(NULL);
	//printArray(a);
	printf("use time = %d\n", end - start);
	return 0;
}

计数排序：

堆排：