快速排序也采用了分治的思想：把原始的数组筛选成较小和较大的两个子数组，然后递归地排序两个子数组。
快速排序算法模板：
void quickSort(int[] nums, int left, int right) {
if (left >= right) {
return;
}
int i = left - 1, j = right + 1;
int x = nums[left];
while (i < j) {
while (nums[++i] < x);
while (nums[--j] > x);
if (i < j) {
int t = nums[i];
nums[i] = nums[j];
nums[j] = t;
}
}
quickSort(nums, left, j);
quickSort(nums, j + 1, right);
}给定你一个长度为 n 的整数数列。
请你使用快速排序对这个数列按照从小到大进行排序。
并将排好序的数列按顺序输出。
输入格式
输入共两行，第一行包含整数 n。
第二行包含 n 个整数（所有整数均在 1∼10^9 范围内），表示整个数列。
输出格式
输出共一行，包含 n 个整数，表示排好序的数列。
数据范围
1≤n≤100000
输入样例：
5
3 1 2 4 5
输出样例：
1 2 3 4 5
N = int(input())
nums = list(map(int, input().split()))
def quick_sort(nums, left, right):
if left >= right:
return
i, j = left - 1, right + 1
x = nums[(left + right) >> 1]
while i < j:
while 1:
i += 1
if nums[i] >= x:
break
while 1:
j -= 1
if nums[j] <= x:
break
if i < j:
nums[i], nums[j] = nums[j], nums[i]
quick_sort(nums, left, j)
quick_sort(nums, j + 1, right)
quick_sort(nums, 0, N - 1)
print(' '.join(list(map(str, nums))))import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
int[] nums = new int[n];
for (int i = 0; i < n; ++i) {
nums[i] = sc.nextInt();
}
quickSort(nums, 0, n - 1);
for (int i = 0; i < n; ++i) {
System.out.print(nums[i] + " ");
}
}
public static void quickSort(int[] nums, int left, int right) {
if (left >= right) {
return;
}
int i = left - 1, j = right + 1;
int x = nums[(left + right) >> 1];
while (i < j) {
while (nums[++i] < x);
while (nums[--j] > x);
if (i < j) {
int t = nums[i];
nums[i] = nums[j];
nums[j] = t;
}
}
quickSort(nums, left, j);
quickSort(nums, j + 1, right);
}
}var buf = '';
process.stdin.on('readable', function () {
var chunk = process.stdin.read();
if (chunk) buf += chunk.toString();
});
let getInputArgs = line => {
return line
.split(' ')
.filter(s => s !== '')
.map(x => parseInt(x));
};
function quickSort(nums, left, right) {
if (left >= right) {
return;
}
let i = left - 1;
let j = right + 1;
let x = nums[(left + right) >> 1];
while (i < j) {
while (nums[++i] < x);
while (nums[--j] > x);
if (i < j) {
const t = nums[i];
nums[i] = nums[j];
nums[j] = t;
}
}
quickSort(nums, left, j);
quickSort(nums, j + 1, right);
}
process.stdin.on('end', function () {
buf.split('\n').forEach(function (line, lineIdx) {
if (lineIdx % 2 === 1) {
nums = getInputArgs(line);
quickSort(nums, 0, nums.length - 1);
console.log(nums.join(' '));
}
});
});package main
import "fmt"
func quickSort(nums []int, left, right int) {
if left >= right {
return
}
i, j := left-1, right+1
x := nums[(left+right)>>1]
for i < j {
for {
i++
if nums[i] >= x {
break
}
}
for {
j--
if nums[j] <= x {
break
}
}
if i < j {
nums[i], nums[j] = nums[j], nums[i]
}
}
quickSort(nums, left, j)
quickSort(nums, j+1, right)
}
func main() {
var n int
fmt.Scanf("%d\n", &n)
nums := make([]int, n)
for i := 0; i < n; i++ {
fmt.Scanf("%d", &nums[i])
}
quickSort(nums, 0, n-1)
for _, v := range nums {
fmt.Printf("%d ", v)
}
}use rand::Rng; // 0.7.2
use std::io;
fn quick_sort(nums: &mut Vec<i32>, left: usize, right: usize) {
if left >= right {
return;
}
let random_index = rand::thread_rng().gen_range(left, right + 1);
let temp = nums[random_index];
nums[random_index] = nums[left];
nums[left] = temp;
let pivot = nums[left];
let mut i = left;
let mut j = right;
while i < j {
while i < j && nums[j] >= pivot {
j -= 1;
}
nums[i] = nums[j];
while i < j && nums[i] < pivot {
i += 1;
}
nums[j] = nums[i];
}
nums[i] = pivot;
quick_sort(nums, left, i);
quick_sort(nums, i + 1, right);
}
fn main() -> io::Result<()> {
let mut n = String::new();
io::stdin().read_line(&mut n)?;
let n = n.trim().parse::<usize>().unwrap();
let mut nums = String::new();
io::stdin().read_line(&mut nums)?;
let mut nums: Vec<i32> = nums.split(' ').map(|s| s.trim().parse().unwrap()).collect();
quick_sort(&mut nums, 0, n - 1);
for num in nums.iter() {
print!("{} ", num);
}
Ok(())
}#include <iostream>
using namespace std;
const int N = 1e6 + 10;
int n;
int nums[N];
void quick_sort(int nums[], int left, int right)
{
if (left >= right) return;
int i = left - 1, j = right + 1;
int x = nums[left + right >> 1];
while (i < j)
{
while (nums[++i] < x);
while (nums[--j] > x);
if (i < j) swap(nums[i], nums[j]);
}
quick_sort(nums, left, j);
quick_sort(nums, j + 1, right);
}
int main()
{
int n;
scanf("%d", &n);
for (int i = 0; i < n; ++i) scanf("%d", &nums[i]);
quick_sort(nums, 0, n - 1);
for (int i = 0; i < n; ++i) printf("%d ", nums[i]);
}