Java--快速排序

代码中为什么 i 和 j 有-1 和 +1呢？ 因为用的是do{}while 循环，会先执行再判断，那么两个指针会先向中间移动一位再判断，所以前面各-+1

import java.util.Scanner;

public class Main {

    static int N = 100100;
    static int[] f = new int[N];
    static int n;

    static void sort(int[] d, int l, int r) {
        if (l >= r) return;
        int x = d[l], i = l - 1, j = r + 1;
        while (i < j) {
            do {
                i++;
            } while (d[i] < x);
            do {
                j--;
            } while (d[j] > x);
            if (i < j) {
                int t = d[i];
                d[i] = d[j];
                d[j] = t;
            }
        }
        sort(d, l, j);
        sort(d, j + 1, r);
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();

        for (int i = 0; i < n; i++) f[i] = sc.nextInt();

        sort(f, 0, n - 1);

        for (int i = 0; i < n; i++) System.out.print(f[i] + " ");
    }
}