8. 快排示例代码：
```cpp
#include <iostream>
(30316)#include <vector>
int partition(std::vector<int>& arr, int low, int high) {
int pivot = arr[high];
int i = low - 1;
for (int j = low; j < high; j++) {
if (arr[j] < pivot) {
i++;
std::swap(arr[i], arr[j]);
}
}
std::swap(arr[i + 1], arr[high]);
return i + 1;
}
void quickSort(std::vector<int>& arr, int low, int high) {
if (low < high) {
int pi = partition(arr, low, high);
quickSort(arr, low, pi - 1);
quickSort(arr, pi + 1, high);
}
}
int main() {
std::vector<int> arr = {8, 4, 2, 7, 1, 5, 9};
int n = arr.size();
quickSort(arr, 0, n - 1);
std::cout << "Sorted array:";
for (auto num : arr) {
std::cout << " " << num;
}
std::cout << std::endl;
return 0;
}
```
