快排再改进
#include <iostream>
using namespace std;void mySwap(int &a, int &b) {int temp = a;a = b;b = temp;
}void insertSort(int a[], int left, int right) {int tmp;int in = 0;int out = 0;for (out = left + 1; out <= right; out++) {tmp = a[out];in = out;while ((in > left) && (a[in - 1] > tmp)) {a[in] = a[in - 1];in--;}a[in] = tmp;}
}long medianOf3(int a[], int left, int right) {int center = (left + right) / 2;if (a[left] > a[center]) mySwap(a[left], a[center]);if (a[left] > a[right]) mySwap(a[left], a[right]);if (a[center] > a[right]) mySwap(a[center], a[right]);mySwap(a[center], a[right - 1]);return a[right - 1];
}int partitionIt(int a[], int left, int right, long pivot) {int leftPtr = left;int rightPtr = right - 1;while (true) {while (a[++leftPtr] < pivot);while (a[--rightPtr] > pivot);if (leftPtr >= rightPtr) {break;}else {mySwap(a[leftPtr], a[rightPtr]);}}mySwap(a[leftPtr], a[right - 1]);return leftPtr;
}void quickSort(int a[], int left, int right) {int size = right - left + 1;if (10 > size) {insertSort(a, left, right);}else {long median = medianOf3(a, left, right);int partition = partitionIt(a, left, right, median);quickSort(a, left, partition - 1);quickSort(a, partition + 1, right);}
}int main() {int a[] = { 149, 192, 66, 66, 47, 152, 159, 195, 61, 66, 17, 168, 118, 64, 27, 80, 30, 105 };int len = (sizeof(a)) / sizeof(a[0]);cout << "排序之前: " << endl;for (int i = 0; i < len; i++) {cout << a[i] << " ";}cout << endl;quickSort(a, 0, len - 1);cout << "排序之后: " << endl;for (int i = 0; i < len; i++) {cout << a[i] << " ";}cout << endl;return 0;
}/*
排序之前:
149 192 66 66 47 152 159 195 61 66 17 168 118 64 27 80 30 105
排序之后:
17 27 30 47 61 64 66 66 66 80 105 118 149 152 159 168 192 195
请按任意键继续. . .
*/
