为什么我的选择排序算法不执行应有的功能（java）？ [英] Why doesn't my selection sort algorithm do what it's supposed to (java)?

问题描述

在过去的几个小时中，我尝试用Java编写选择排序算法，而无需查看完成的代码。我刚刚（通过文字）阅读了该算法的工作原理。

In the last hours I have tried to write the selection sort algorithm in Java without looking at finished code. I just read how the algorithm works (by words).

我不会复制粘贴说明，而是进行描述（以检查我是否理解）：

I won't copy paste the explanation but rather depict it (to check if I understood it):

-我们有一个未排序的数组A和一个空数组B（其大小与A相同）

-We have one unsorted array A and an empty array B (which has the same size as A)

-现在，请使用未排序的数组A并找到其最小元素。找到的最小元素，现在将其与未排序数组A的第一个元素切换

-Now take the unsorted array A and find its smallest element. Smallest element found, now switch this element with the first element of the unsorted array A

-将第一个元素（=数组A的最小元素）放入数组B

-Put the first element (=smallest element of array A) into the array B

-重复直到完成A的每个元素

-Repeat till we are done with every element of A

我尝试用Java编写代码：

I tried to code that in Java:

public class Selectionsort{

    public static void main(String[] args) {
        int[] myArray = {9,6,1,3,0,4,2};
        int[] B = new int[myArray.length];

        for(int i=0; i<myArray.length; i++) {
            B[i]=findMIN(myArray, i);
        }
    }

    static int findMIN(int[] A, int c) {
        int x = A[c];
        while(c<A.length) {
            if(x>A[c]) {
                x=A[c];
            }
            c++;
        }
        return x;
    }
}

但是我得到了一个奇怪的输出：

But I get a weird output:

0 0 0 0 0 2 2 

推荐答案

首先，修复您的 findMIN ，您应该返回最小值的 index 元素（并将当前值的元素与最小值进行比较）。例如，

First, fix your findMIN, you should return the index of the minimum element (and compare the element at the current value to the minimum). Like,

static int findMIN(int[] A, int c) {
    int x = c;
    for (; c < A.length; c++) {
        if (A[c] < A[x]) {
            x = c;
        }
    }
    return x;
}

然后我将使用交换方法，例如

Then I would use a swap method, like

static void swap(int[] A, int a, int b) {
    if (a != b) {
        int t = A[a];
        A[a] = A[b];
        A[b] = t;
    }
}

最后，将其绑在一起

public static void main(String[] args) {
    int[] myArray = { 9, 6, 1, 3, 0, 4, 2 };

    for (int i = 0; i < myArray.length; i++) {
        swap(myArray, i, findMIN(myArray, i));
    }
    System.out.println(Arrays.toString(myArray));
}

然后，我得到

[0, 1, 2, 3, 4, 6, 9]

这篇关于为什么我的选择排序算法不执行应有的功能（java）？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！