题解 | 【模板】排序

import java.util.Scanner;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.StreamTokenizer;
// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
     public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StreamTokenizer in = new StreamTokenizer(br);

        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));

        in.nextToken();
        int n = (int) in.nval;

        int[] a = new int[n];

        for (int i = 0; i < n; i++) {
            in.nextToken();
            a[i] = (int) in.nval;
        }

        quickSort(a, 0, n-1);

        for (int k = 0; k < n - 1; k++) {
            out.print(a[k] + " ");
        }
        out.println(a[n - 1]);
        out.flush();
        out.close();
        br.close();

    }

    private static void quickSort(int[] arr,int low,int high){
        if(low<high){
                   int pivot = partition(arr,low,high);
        quickSort(arr, low, pivot-1);
                quickSort(arr, pivot+1,high); 
        }

    }

    private static int partition(int[] arr,int low,int high){
        int pivot = arr[low];
        int i = low;

        for(int j= low+1;j<=high;j++){
            if(arr[j]<pivot){
                i++;
                swap(arr, i, j);
            }
        }
        swap(arr, low, i);
        return i;
    }

    private static void swap(int[] arr,int i, int j) {
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }
}