public static String deleSubSet() {

        char[] parent = {'0','1','2','3','4','5','6','7','8','9'};
    
        Arrays.sort(parent);
        
        char[] subSet = {'6','3','4',};
        
        Arrays.sort(subSet);

        StringBuffer sb = new StringBuffer();

        for (int i = 0, k = 0; i < parent.length; i++) {

            if (parent[i] == subSet[k]) {
                k++;
                
            } else {
                sb.append(parent[i]);
            }
        }

        return sb.toString();

    }

for (int i = 0, k = 0; i < parent.length; i++) {

            if (k<subSet.length && i<parent.length && parent[i] == subSet[k]) {
                k++;
            } else {
                sb.append(parent[i]);
            }
        }

------解决方案--------------------
你的问题在于会把k值增加到大于subSet的范围，引发异常，1楼加上了判断处理，就避免了这个问题，不过1楼if里的i<parent.length这个就没有必要了。

------解决方案--------------------


------解决方案--------------------
Java code

import java.util.*;

public class Del
{
    public static void main(String[] args) {
        
        char[] parent = {'0','1','2','3','4','5','6','7','8','9'};
    
        Arrays.sort(parent);
        
        char[] subSet = {'6','3','4',};
        
        Arrays.sort(subSet);

        StringBuffer sb = new StringBuffer();

        for (int i = 0, k = 0; i < parent.length; i++) {

            if (k<subSet.length && parent[i] == subSet[k]) {
                k++;
                
            } else {
                sb.append(parent[i]);
            }
        }

        System.out.println(sb);

        //return sb.toString();
    }
}

------解决方案--------------------
用API更简单
Java code

    public static String deleSubSet() {
        Character[] parent = {'0','1','2','3','4','5','6','7','8','9'};       
        Character[] subSet = {'6','3','4',};
        ArrayList<Character> pArrayList = new ArrayList<Character>();
        ArrayList<Character> sArrayList = new ArrayList<Character>();
        pArrayList.addAll(Arrays.asList(parent));
        sArrayList.addAll(Arrays.asList(subSet));
        pArrayList.removeAll(sArrayList);
        return pArrayList.toString();
    }

------解决方案--------------------
探讨


Java code

import java.util.*;

public class Del
{
    public static void main(String[] args) {
        
        char[] parent = {'0','1','2','3','4','5','6','7','8','9'};
    
        Arrays.sort(p……