Quick

简书 賈小強
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package com.lab1.test2;

public class Quick {
    public static void main(String[] args) {
        Comparable[] a = { 5, 3, 1, 2, 4 };
        sort(a);
        show(a);
    }

    private static void show(Comparable[] a) {
        for (int i = 0; i < a.length; i++) {
            System.out.print(a[i] + " ");
        }
    }

    private static void sort(Comparable[] a) {
        sort(a, 0, a.length - 1);
    }

    private static void sort(Comparable[] a, int lo, int hi) {
        if (lo >= hi) {
            return;
        }
        int j = partition(a, lo, hi);
        sort(a, lo, j - 1);
        sort(a, j + 1, hi);
    }

    private static int partition(Comparable[] a, int lo, int hi) {
        int i = lo;
        int j = hi + 1;
        while (true) {
            while (less(a, ++i, lo)) {
                if (i == hi) {
                    break;
                }
            }
            while (less(a, lo, --j)) {
                if (j == lo) {
                    break;
                }
            }
            if (i >= j) {
                break;
            }
            exch(a, i, j);
        }
        exch(a, lo, j);
        return j;
    }

    private static void exch(Comparable[] a, int i, int j) {
        Comparable temp = a[i];
        a[i] = a[j];
        a[j] = temp;
    }

    private static boolean less(Comparable[] a, int i, int j) {
        return a[i].compareTo(a[j]) < 0;
    }
}

输出

1 2 3 4 5 

Happy learning !!