Quicksort

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <time.h>#define BUFSIZE 19void swap(int *arr, int i, int j){int tmp = arr[i];arr[i] = arr[j];arr[j] = tmp;}int Random(int left, int right){time_t t;srand((unsigned int)time(&t));return left + rand() % (right-left+1);}int Partition(int *arr, int left, int right){int pivot = arr[right];int j = left;for (int i = left; i < right; i++) {if (arr[i] <= pivot)swap(arr, j++, i);}swap(arr, j, right);return j;}int PartitionA(int *arr, int left, int right){int pivot = arr[right];int j = left - 1;for (int i = left; i < right; i++) {if (arr[i] <= pivot)swap(arr, ++j, i);}swap(arr, j + 1, right);return j + 1;}int PartitionB(int *arr, int left, int right){// 选中间元素作为枢纽swap(arr, left, (left + right) / 2); int pivot = arr[left];int j = left;for (int i = left + 1; i <= right; i++) {if (arr[i] <= pivot)swap(arr, ++j, i);}swap(arr, j, left);return j;}int PartitionC(int *arr, int left, int right){int last = Random(left, right); // 随机化快排swap(arr, right, last);int pivot = arr[right];int j = left - 1;for (int i = left; i < right; i++) {if (arr[i] <= pivot)swap(arr, ++j, i);}swap(arr, j + 1, right);return j + 1;}int Partition1(int *arr, int left, int right){int pivot = arr[left];while (left < right) { // [) ro (]// 从右边开始while (left < right && arr[right] >= pivot) right--;arr[left] = arr[right];while (left < right && arr[left] <= pivot)left++;arr[right] = arr[left];}arr[left] = pivot;return right;}int Partition2(int *arr, int left, int right){int pivot = arr[right];while (left < right) {// 从左边开始while (left < right && arr[left] <= pivot) left++;arr[right] = arr[left];while (left < right && arr[right] >= pivot)right--;arr[left] = arr[right];}arr[right] = pivot;return left;}int Partition3(int *arr, int left, int right){int pivot = arr[right];int end = right;while (left < right) { while (left < right && arr[left] <= pivot) left++;while (left < right && arr[right] >= pivot)right--;if (left < right)swap(arr, left, right);}if (right != end)swap(arr, right, end);return left; // 谁先操作返回谁}int Partition4(int *arr, int left, int right){int pivot = arr[left];int i = left - 1;int j = right + 1;while (1) {while (arr[--j] > pivot);while (arr[++i] <= pivot);if (i < j)swap(arr, i, j);else break;}swap(arr, left, j);return j;}// 如何证明它有bug? ^-^int Partition5(int *arr, int left, int right){int pivot = arr[left];int i = left - 1;int j = right + 1;while (i < j) {while (i < j && arr[--j] > pivot);while (i < j && arr[++i] < pivot);// do {// j--;// } while (arr[j] > pivot);// do {// i++;// } while (arr[i] < pivot);if (i < j)swap(arr, i, j);elsereturn j;}}void QuickSort(int *arr, int left, int right){if (left >= right)return ;int pivot = PartitionC(arr, left, right);QuickSort(arr, left, pivot - 1);QuickSort(arr, pivot + 1, right);}void StoogeSort(int *arr, int left, int right){if (arr[left] > arr[right])swap(arr, left, right);if (left + 1 >= right)return ;int k = (right - left + 1) / 3;StoogeSort(arr, left, right - k);StoogeSort(arr, left + k, right);StoogeSort(arr, left, right - k);}#define MAX_BUF 256int numcmp(char *pa, char *pb){return (*(int *)pa - *(int *)pb);}void *mybsearch(const void *key, const void *base,size_t n, size_t size,int (*cmp)(const void *, const void *)){const char *p;size_t m;for (p = (const char *)base, m = n; m > 0; ) {const size_t pivot = n >> 1;const char *const q = p + size * pivot;const int val = (*cmp)(key, q);if (val < 0) { /* search below pivot */ n = pivot;} else if (val == 0) {return ((void *)q);} else { /* search above pivot */ p = q + size;n -= pivot + 1;}}return NULL;}// 如part3框架一样void myqsort(void *base, size_t n, size_t size, int (*cmp)(const void *, const void *)){while (1 < n) {size_t i = 0;size_t j = n - 1;char *qi = (char *)base;char *qj = qi + size * j; // 指向最后一个元素char *qp = qj; // 选择最后一个点作为pivotwhile (i < j) {while (i < j && (*numcmp)(qi, qp) <= 0)++i, qi += size;while (i < j && (*numcmp)(qp, qj) <= 0)--j, qj -= size;if (i < j) {  /* swap elements i and j */char buf[MAX_BUF];char *q1 = qi;char *q2 = qj;size_t m, ma;for (ma = size; 0 < ma; ma -= m, q1 += m, q2 -= m) {m = ma < sizeof(buf) ? ma : sizeof(buf);memcpy(buf, q1, m);memcpy(q1, q2, m);memcpy(q2, buf, m);}++i, qi += size;}}/* swap elements i and pivot */if (qi != qp) { char buf[MAX_BUF];char *q1 = qi;char *q2 = qp;size_t m, ma;for (ma = size; 0 < ma; ma -= m, q1 += m, q2 -= m) {m = ma < sizeof(buf) ? ma : sizeof(buf);memcpy(buf, q1, m);memcpy(q1, q2, m);memcpy(q2, buf, m);}}j = n - i - 1;qi += size;if (j < i) { /* recurse on smaller partition */if (1 < j)qsort(qi, j, size, cmp);n = i;} else { /* lower partition is smaller */if (1 < i)qsort(base, i, size, cmp);base = qi;n = j;}}}int main(){int arr[] = {17, 5, 9, 21, 6, 123, 24, 8, 34, 324, 3, 23, 54, 22, 57, 234, 7, 12, 234};/*int arr[8] = {234, 123, 76, 76, 54, 43, 32, 21};*/               /*int arr[8] = {1, 45, 43, 45, 65, 45, 87, 353};*/int len = sizeof(arr) / sizeof(arr[0]);printf("array:");for (int i = 0; i < len; i++) {printf("%-8d", arr[i]);}printf("\n");QuickSort(arr, 0, len - 1);//StoogeSort(arr, 0, BUFSIZE - 1);//myqsort(arr, BUFSIZE, sizeof(int), (int (*)(const void *, const void *))numcmp);printf("quick:");for (int i = 0; i < len; i++) {printf("%d\t", arr[i]);}printf("\n");getchar();return 0;}