Question

是否可以使用插入排序算法对字符串开头的元音进行排序？

我尝试了很多，但没有得到，有人暗示如何实现它，或者我应该使用其他排序算法吗？

    static char[] text = "thisIsAString".toCharArray();

    static void instertionSort() {
        for (int i = 0; i < text.length; i++) {
            char h = text[i];
            int j = i - 1;

            while ((j >= 0) && Character.toLowerCase(text[j]) > Character.toLowerCase(h)) {

                    text[j+1] = text[j];
                    j = j - 1;

            }

            text[j+1] = h;
        }
    }

示例：“ thisIsAString”->“ AiiIghnrssStt”

Answer 1

您可以为此使用插入排序（就像其他所有排序算法一样，它们都相等。只是对字段进行排序所花费的时间不同，但是结果始终相同）。

算法中的问题是您不检查比较的字符是元音还是大写/小写。

此代码应该有效：

public class StringSorter {

    private static final String vowels = "aeiou";

    public static void main(String[] args) {
        char[] string = "thisIsAString".toCharArray();
        char[] test2 = "thisIsAStringaAabBs".toCharArray();

        System.out.println("unsorted: " + new String(string));
        insertionSort(string);
        System.out.println("sorted:   " + new String(string));

        System.out.println();

        System.out.println("unsorted: " + new String(test2));
        insertionSort(test2);
        System.out.println("sorted:   " + new String(test2));
    }

    public static void insertionSort(char[] string) {
        for (int i = 1; i < string.length; i++) {
            char h = string[i];
            int j = i;

            while ((j > 0) && isBefore(string[j - 1], h)) {

                string[j] = string[j - 1];
                j = j - 1;

            }

            string[j] = h;
        }
    }

    private static boolean isBefore(char a, char b) {
        String lowA = Character.toString(Character.toLowerCase(a));
        String lowB = Character.toString(Character.toLowerCase(b));

        if (vowels.contains(lowA)) {
            if (vowels.contains(lowB)) {
                //both are vowels
                return chooseLowerCaseFirst(a, b);
            }
            else {
                //only a is a vowel
                return false;
            }
        }
        else if (vowels.contains(lowB)) {
            //only b is a vowel
            return true;
        }
        else {
            //none is a vowel
            return chooseLowerCaseFirst(a, b);
        }
    }

    private static boolean chooseLowerCaseFirst(char a, char b) {
        String lowA = Character.toString(Character.toLowerCase(a));
        String lowB = Character.toString(Character.toLowerCase(b));

        if (lowA.equals(lowB)) {
            //both are the same character

            if (Character.isLowerCase(a)) {
                if (Character.isLowerCase(b)) {
                    //both are lower case
                    return Character.toLowerCase(a) > Character.toLowerCase(b);
                }
                else {
                    //only a is lower case
                    return false;
                }
            }
            else if (Character.isLowerCase(b)) {
                //only b is lower case
                return true;
            }
            else {
                //both are upper case
                return Character.toLowerCase(a) > Character.toLowerCase(b);
            }
        }
        else {
            //different characters
            return Character.toLowerCase(a) > Character.toLowerCase(b);
        }
    }
}

生成的输出是：

unsorted: thisIsAString
sorted:   AiiIghnrssStt

unsorted: thisIsAStringaAabBs
sorted:   aaAAiiIbBghnrsssStt

Answer 2

如果您还在考虑其他方法，则可以从Java 8中混合使用this pen和streams。

import java.util.*;
import java.util.stream.Collectors;

public class Main {
    private static List<Character> order = new ArrayList<>(Arrays.asList('a', 'A', 'e', 'E', 'i', 'I', 'o', 'O', 'u', 'U', 'b', 'B', 'c', 'C', 'd', 'D', 'f', 'F', 'g', 'G', 'h', 'H', 'j', 'J', 'k', 'K', 'l', 'L', 'm', 'M', 'n', 'N', 'p', 'P', 'q', 'Q', 'r', 'R', 's', 'S', 't', 'T', 'v', 'V', 'w', 'W', 'x', 'X', 'y', 'Y', 'z', 'Z'));

    public static void main(String[] args) {
        String example = "thisIsAString";
        List<Character> cl = example.chars().mapToObj(c -> (char) c).collect(Collectors.toList());
        List<Character> ls = cl.stream().sorted(Comparator.comparingInt(order::indexOf)).collect(Collectors.toCollection(ArrayList::new));
        StringBuilder result = new StringBuilder();
        for (Character c : ls) result.append(c);
        System.out.println(result);
    }
}

使用插入排序对字符串开头的元音进行排序

2 个答案: