suspicioussort.java

来自「java中的一些难题」· Java 代码 · 共 40 行

import java.util.*;

public class SuspiciousSort {
    public static void main(String[] args) {
        Random rnd = new Random();
        Integer[] arr = new Integer[100];

        for (int i = 0; i < arr.length; i++)
            arr[i] = rnd.nextInt();

        Comparator<Integer> cmp = new Comparator<Integer>() {
            public int compare(Integer i1, Integer i2) {
                return i2 - i1;
            }
        };
        Arrays.sort(arr, cmp);
        System.out.println(order(arr));
    }

    enum Order { ASCENDING, DESCENDING, CONSTANT, UNORDERED };

    static Order order(Integer[] a) {
        boolean ascending  = false;
        boolean descending = false;

        for (int i = 1; i < a.length; i++) {
            ascending  |= a[i] > a[i-1];
            descending |= a[i] < a[i-1];
        }

        if (ascending  && !descending)
            return Order.ASCENDING;
        if (descending && !ascending)
            return Order.DESCENDING;
        if (!ascending)
            return Order.CONSTANT;   // All elements equal 
        return Order.UNORDERED;      // Array is not sorted 
    } 
}