算法删除字符串中出现次数最少的字符

Posted 2022-06-23 Bug挖掘机

题目描述

实现删除字符串中出现次数最少的字符，若多个字符出现次数一样，则都删除。输出删除这些单词后的字符串，字符串中其它字符保持原来的顺序。

方法一

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class removetheleast 
    //删除字符串中出现次数最少的字符
    public static String removetheleast() 
        //输入
        Scanner s1 = new Scanner(System.in);
        String input_str = s1.nextLine();
        char[] c1 = input_str.toCharArray();

        //统计字符出现的次数
        Map<Character, Integer> m1 = new HashMap<>();
        for (int i = 0; i < c1.length; i++) 
            if (m1.containsKey(c1[i])) 
                m1.put(c1[i], m1.get(c1[i]) + 1);
             else 
                m1.put(c1[i], 1);
            
        

        ArrayList<Character> list_min = new ArrayList<>();
        int min = 800;
        for (char j : m1.keySet()) 
            if (m1.get(j) < min) 
                min = m1.get(j);
                list_min.clear();
                list_min.add(j);
             else if (m1.get(j) == min) 
                list_min.add(j);
            
        

        String res = "";
        //清除最少的字符串
        for (int x = 0; x < c1.length; x++) 
            if (!list_min.contains(c1[x])) 
                res += c1[x];
            
        
        return res;
    

方法二（使用到StringBuilder）

import java.util.*;
  
public class Main
    public static void main(String[] args)
        Scanner in = new Scanner(System.in);
        while(in.hasNext())
            String s = in.nextLine();
            int[] a = new int[26];
            for(int i=0;i<s.length();i++)
                a[s.charAt(i)-97]++;
            
            int min = 21;
            //找出出现最小的次数
            for(int i=0;i<26;i++)
                if(a[i]<min && a[i]>0)
                    min = a[i];
                
            
            StringBuilder toBeDeleted = new StringBuilder();
            for(int i=0;i<26;i++)
                if(a[i]==min)
                    char c = (char)(a+i);
                    toBeDeleted.append(c);
                
            
            String str = toBeDeleted.toString();
            StringBuilder res = new StringBuilder();
            for(int i=0;i<s.length();i++)
                if(!str.contains(s.charAt(i)+""))
                    res.append(s.charAt(i));
                
            
            System.out.println(res);
        
    
      

参考链接​